lyttle21.bib

@article{Abadi.Barham.ea2016,
  title = {{{TensorFlow}}: {{A}} System for Large-Scale Machine Learning},
  shorttitle = {{{TensorFlow}}},
  author = {Abadi, Mart{\'i}n and Barham, Paul and Chen, Jianmin and Chen, Zhifeng and Davis, Andy and Dean, Jeffrey and Devin, Matthieu and Ghemawat, Sanjay and Irving, Geoffrey and Isard, Michael and Kudlur, Manjunath and Levenberg, Josh and Monga, Rajat and Moore, Sherry and Murray, Derek G. and Steiner, Benoit and Tucker, Paul and Vasudevan, Vijay and Warden, Pete and Wicke, Martin and Yu, Yuan and Zheng, Xiaoqiang},
  year = {2016},
  month = may,
  abstract = {TensorFlow is a machine learning system that operates at large scale and in heterogeneous environments. TensorFlow uses dataflow graphs to represent computation, shared state, and the operations that mutate that state. It maps the nodes of a dataflow graph across many machines in a cluster, and within a machine across multiple computational devices, including multicore CPUs, general-purpose GPUs, and custom designed ASICs known as Tensor Processing Units (TPUs). This architecture gives flexibility to the application developer: whereas in previous "parameter server" designs the management of shared state is built into the system, TensorFlow enables developers to experiment with novel optimizations and training algorithms. TensorFlow supports a variety of applications, with particularly strong support for training and inference on deep neural networks. Several Google services use TensorFlow in production, we have released it as an open-source project, and it has become widely used for machine learning research. In this paper, we describe the TensorFlow dataflow model in contrast to existing systems, and demonstrate the compelling performance that TensorFlow achieves for several real-world applications.},
  archiveprefix = {arXiv},
  eprint = {1605.08695},
  journal = {ArXiv e-prints},
  keywords = {and Cluster Computing,Computer Science - Artificial Intelligence,Computer Science - Distributed,Parallel},
  primaryclass = {cs.DC}
}

@article{Addison.Wright.ea2021,
  title = {{{TOI}}-257b ({{HD}} 19916b): A Warm Sub-Saturn Orbiting an Evolved {{F}}-Type Star},
  shorttitle = {{{TOI}}-257b ({{HD}} 19916b)},
  author = {Addison, Brett C. and Wright, Duncan J. and Nicholson, Belinda A. and Cale, Bryson and Mocnik, Teo and Huber, Daniel and Plavchan, Peter and Wittenmyer, Robert A. and Vanderburg, Andrew and Chaplin, William J. and Chontos, Ashley and Clark, Jake T. and Eastman, Jason D. and Ziegler, Carl and Brahm, Rafael and Carter, Bradley D. and Clerte, Mathieu and Espinoza, N{\'e}stor and Horner, Jonathan and Bentley, John and Jord{\'a}n, Andr{\'e}s and Kane, Stephen R. and Kielkopf, John F. and Laychock, Emilie and Mengel, Matthew W. and Okumura, Jack and Stassun, Keivan G. and Bedding, Timothy R. and Bowler, Brendan P. and Burnelis, Andrius and {Blanco-Cuaresma}, Sergi and Collins, Michaela and Crossfield, Ian and Davis, Allen B. and Evensberget, Dag and Heitzmann, Alexis and Howell, Steve B. and Law, Nicholas and Mann, Andrew W. and Marsden, Stephen C. and Matson, Rachel A. and O'Connor, James H. and Shporer, Avi and Stevens, Catherine and Tinney, C. G. and Tylor, Christopher and Wang, Songhu and Zhang, Hui and Henning, Thomas and Kossakowski, Diana and Ricker, George and Sarkis, Paula and Schlecker, Martin and Torres, Pascal and Vanderspek, Roland and Latham, David W. and Seager, Sara and Winn, Joshua N. and Jenkins, Jon M. and Mireles, Ismael and Rowden, Pam and Pepper, Joshua and Daylan, Tansu and Schlieder, Joshua E. and Collins, Karen A. and Collins, Kevin I. and Tan, Thiam-Guan and Ball, Warrick H. and Basu, Sarbani and Buzasi, Derek L. and Campante, Tiago L. and Corsaro, Enrico and {Gonz{\'a}lez-Cuesta}, L. and Davies, Guy R. and {de Almeida}, Leandro and {do Nascimento}, Jr., Jose-Dias and Garc{\'i}a, Rafael A. and Guo, Zhao and Handberg, Rasmus and Hekker, Saskia and Hey, Daniel R. and Kallinger, Thomas and Kawaler, Steven D. and Kayhan, Cenk and Kuszlewicz, James S. and Lund, Mikkel N. and Lyttle, Alexander and Mathur, Savita and Miglio, Andrea and Mosser, Benoit and Nielsen, Martin B. and Serenelli, Aldo M. and Aguirre, Victor Silva and Theme{\ss}l, Nathalie},
  year = {2021},
  month = apr,
  volume = {502},
  pages = {3704--3722},
  issn = {0035-8711},
  doi = {10.1093/mnras/staa3960},
  abstract = {We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the MINERVA-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of MP = 0.138 {$\pm$} 0.023 \$\textbackslash rm \{M\_J\}\$ (43.9 {$\pm$} 7.3 \$\textbackslash, M\_\{\textbackslash rm \textbackslash oplus\}\$ ), a radius of RP = 0.639 {$\pm$} 0.013 \$\textbackslash rm \{R\_J\}\$ (7.16 {$\pm$} 0.15 \$\textbackslash, \textbackslash mathrm\{ R\}\_\{\textbackslash rm \textbackslash oplus\}\$ ), bulk density of \$0.65\^\{+0.12\}\_\{-0.11\}\$ (cgs), and period \$18.38818\^\{+0.00085\}\_\{-0.00084\}\$ \$\textbackslash rm \{days\}\$ . TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M* = 1.390 {$\pm$} 0.046 \$\textbackslash rm \{M\_\{sun\}\}\$ , R* = 1.888 {$\pm$} 0.033 \$\textbackslash rm \{R\_\{sun\}\}\$ , Teff = 6075 {$\pm$} 90 \$\textbackslash rm \{K\}\$ , and vsin i = 11.3 {$\pm$} 0.5 km s-1. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a {$\sim$}71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars ({$\sim$}100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.},
  author+an = {87=highlight},
  journal = {Monthly Notices of the Royal Astronomical Society},
  keywords = {asteroseismology,planetary systems,stars: individual (TIC 200723869/TOI-257),techniques: photometric,techniques: radial velocities,techniques: spectroscopic}
}

@article{Ahumada.Prieto.ea2020,
  title = {The 16th Data Release of the Sloan Digital Sky Surveys: {{First}} Release from the {{APOGEE}}-2 Southern Survey and Full Release of {{eBOSS}} Spectra},
  author = {Ahumada, Romina and Prieto, Carlos Allende and Almeida, Andr{\'e}s and Anders, Friedrich and Anderson, Scott F. and Andrews, Brett H. and Anguiano, Borja and Arcodia, Riccardo and Armengaud, Eric and Aubert, Marie and Avila, Santiago and {Avila-Reese}, Vladimir and Badenes, Carles and Balland, Christophe and Barger, Kat and {Barrera-Ballesteros}, Jorge K. and Basu, Sarbani and Bautista, Julian and Beaton, Rachael L. and Beers, Timothy C. and Benavides, B. Izamar T. and Bender, Chad F. and Bernardi, Mariangela and Bershady, Matthew and Beutler, Florian and Bidin, Christian Moni and Bird, Jonathan and Bizyaev, Dmitry and Blanc, Guillermo A. and Blanton, Michael R. and Boquien, M{\'e}d{\'e}ric and Borissova, Jura and Bovy, Jo and Brandt, W. N. and Brinkmann, Jonathan and Brownstein, Joel R. and Bundy, Kevin and Bureau, Martin and Burgasser, Adam and Burtin, Etienne and {Cano-D{\'i}az}, Mariana and Capasso, Raffaella and Cappellari, Michele and Carrera, Ricardo and Chabanier, Sol{\`e}ne and Chaplin, William and Chapman, Michael and Cherinka, Brian and Chiappini, Cristina and Doohyun Choi, Peter and Chojnowski, S. Drew and Chung, Haeun and Clerc, Nicolas and Coffey, Damien and Comerford, Julia M. and Comparat, Johan and {da Costa}, Luiz and Cousinou, Marie-Claude and Covey, Kevin and Crane, Jeffrey D. and Cunha, Katia and Ilha, Gabriele da Silva and Dai, Yu Sophia and Damsted, Sanna B. and Darling, Jeremy and Davidson, James W., Jr. and Davies, Roger and Dawson, Kyle and De, Nikhil and {de la Macorra}, Axel and De Lee, Nathan and Queiroz, Anna B{\'a}rbara de Andrade and Deconto Machado, Alice and {de la Torre}, Sylvain and Dell'Agli, Flavia and {du Mas des Bourboux}, H{\'e}lion and {Diamond-Stanic}, Aleksandar M. and Dillon, Sean and Donor, John and Drory, Niv and Duckworth, Chris and Dwelly, Tom and Ebelke, Garrett and Eftekharzadeh, Sarah and Davis Eigenbrot, Arthur and Elsworth, Yvonne P. and Eracleous, Mike and Erfanianfar, Ghazaleh and Escoffier, Stephanie and Fan, Xiaohui and Farr, Emily and {Fern{\'a}ndez-Trincado}, Jos{\'e} G. and Feuillet, Diane and Finoguenov, Alexis and Fofie, Patricia and {Fraser-McKelvie}, Amelia and Frinchaboy, Peter M. and Fromenteau, Sebastien and Fu, Hai and Galbany, Llu{\'i}s and Garcia, Rafael A. and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Oehmichen, Luis Alberto Garma and Ge, Junqiang and Maia, Marcio Antonio Geimba and Geisler, Doug and Gelfand, Joseph and Goddy, Julian and {Gonzalez-Perez}, Violeta and Grabowski, Kathleen and Green, Paul and Grier, Catherine J. and Guo, Hong and Guy, Julien and Harding, Paul and Hasselquist, Sten and Hawken, Adam James and Hayes, Christian R. and Hearty, Fred and Hekker, S. and Hogg, David W. and Holtzman, Jon A. and Horta, Danny and Hou, Jiamin and Hsieh, Bau-Ching and Huber, Daniel and Hunt, Jason A. S. and Chitham, J. Ider and Imig, Julie and Jaber, Mariana and Angel, Camilo Eduardo Jimenez and Johnson, Jennifer A. and Jones, Amy M. and J{\"o}nsson, Henrik and Jullo, Eric and Kim, Yerim and Kinemuchi, Karen and Kirkpatrick, Charles C., IV and Kite, George W. and Klaene, Mark and Kneib, Jean-Paul and Kollmeier, Juna A. and Kong, Hui and Kounkel, Marina and Krishnarao, Dhanesh and Lacerna, Ivan and Lan, Ting-Wen and Lane, Richard R. and Law, David R. and Le Goff, Jean-Marc and Leung, Henry W. and Lewis, Hannah and Li, Cheng and Lian, Jianhui and Lin, Lihwai and Long, Dan and {Longa-Pe{\~n}a}, Pen{\'e}lope and Lundgren, Britt and Lyke, Brad W. and Ted Mackereth, J. and MacLeod, Chelsea L. and Majewski, Steven R. and Manchado, Arturo and Maraston, Claudia and Martini, Paul and Masseron, Thomas and Masters, Karen L. and Mathur, Savita and McDermid, Richard M. and Merloni, Andrea and Merrifield, Michael and M{\'e}sz{\'a}ros, Szabolcs and Miglio, Andrea and Minniti, Dante and Minsley, Rebecca and Miyaji, Takamitsu and Mohammad, Faizan Gohar and Mosser, Benoit and Mueller, Eva-Maria and Muna, Demitri and {Mu{\~n}oz-Guti{\'e}rrez}, Andrea and Myers, Adam D. and Nadathur, Seshadri and Nair, Preethi and Nandra, Kirpal and {do Nascimento}, Janaina Correa and Nevin, Rebecca Jean and Newman, Jeffrey A. and Nidever, David L. and Nitschelm, Christian and Noterdaeme, Pasquier and O'Connell, Julia E. and Olmstead, Matthew D. and Oravetz, Daniel and Oravetz, Audrey and Osorio, Yeisson and Pace, Zachary J. and Padilla, Nelson and {Palanque-Delabrouille}, Nathalie and Palicio, Pedro A. and Pan, Hsi-An and Pan, Kaike and Parker, James and Paviot, Romain and Peirani, Sebastien and Ram{\'r}ez, Karla Pe{\~n}a and Penny, Samantha and Percival, Will J. and {Perez-Fournon}, Ismael and {P{\'e}rez-R{\`a}fols}, Ignasi and Petitjean, Patrick and Pieri, Matthew M. and Pinsonneault, Marc and Poovelil, Vijith Jacob and Povick, Joshua Tyler and Prakash, Abhishek and {Price-Whelan}, Adrian M. and Raddick, M. Jordan and Raichoor, Anand and Ray, Amy and Rembold, Sandro Barboza and Rezaie, Mehdi and Riffel, Rogemar A. and Riffel, Rog{\'e}rio and Rix, Hans-Walter and Robin, Annie C. and {Roman-Lopes}, A. and {Rom{\'a}n-Z{\'u}{\~n}iga}, Carlos and Rose, Benjamin and Ross, Ashley J. and Rossi, Graziano and Rowlands, Kate and Rubin, Kate H. R. and Salvato, Mara and S{\'a}nchez, Ariel G. and {S{\'a}nchez-Menguiano}, Laura and {S{\'a}nchez-Gallego}, Jos{\'e} R. and Sayres, Conor and Schaefer, Adam and Schiavon, Ricardo P. and Schimoia, Jaderson S. and Schlafly, Edward and Schlegel, David and Schneider, Donald P. and Schultheis, Mathias and Schwope, Axel and Seo, Hee-Jong and Serenelli, Aldo and Shafieloo, Arman and Shamsi, Shoaib Jamal and Shao, Zhengyi and Shen, Shiyin and Shetrone, Matthew and Shirley, Raphael and Aguirre, V{\'i}ctor Silva and Simon, Joshua D. and Skrutskie, M. F. and Slosar, An{\v z}e and Smethurst, Rebecca and Sobeck, Jennifer and Sodi, Bernardo Cervantes and Souto, Diogo and Stark, David V. and Stassun, Keivan G. and Steinmetz, Matthias and Stello, Dennis and Stermer, Julianna and {Storchi-Bergmann}, Thaisa and Streblyanska, Alina and Stringfellow, Guy S. and Stutz, Amelia and Su{\'a}rez, Genaro and Sun, Jing and {Taghizadeh-Popp}, Manuchehr and Talbot, Michael S. and Tayar, Jamie and Thakar, Aniruddha R. and Theriault, Riley and Thomas, Daniel and Thomas, Zak C. and Tinker, Jeremy and Tojeiro, Rita and Toledo, Hector Hernandez and Tremonti, Christy A. and Troup, Nicholas W. and Tuttle, Sarah and {Unda-Sanzana}, Eduardo and Valentini, Marica and {Vargas-Gonz{\'a}lez}, Jaime and {Vargas-Maga{\~n}a}, Mariana and {V{\'a}zquez-Mata}, Jose Antonio and Vivek, M. and Wake, David and Wang, Yuting and Weaver, Benjamin Alan and Weijmans, Anne-Marie and Wild, Vivienne and Wilson, John C. and Wilson, Robert F. and Wolthuis, Nathan and {Wood-Vasey}, W. M. and Yan, Renbin and Yang, Meng and Y{\`e}che, Christophe and Zamora, Olga and Zarrouk, Pauline and Zasowski, Gail and Zhang, Kai and Zhao, Cheng and Zhao, Gongbo and Zheng, Zheng and Zheng, Zheng and Zhu, Guangtun and Zou, Hu},
  year = {2020},
  month = jul,
  volume = {249},
  pages = {3},
  doi = {10.3847/1538-4365/ab929e},
  abstract = {This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library ``MaStar''). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  adsurl = {https://ui.adsabs.harvard.edu/abs/2020ApJS..249....3A},
  archiveprefix = {arXiv},
  eid = {3},
  eprint = {1912.02905},
  eprinttype = {arxiv},
  keywords = {1174,1378,1624,1630,2002,786,83,Astronomy databases,Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics,Astrophysics - Instrumentation and Methods for Astrophysics,Galactic abundances,Infrared astronomy,Optical telescopes,Redshift surveys,Stellar properties,Stellar spectral lines},
  number = {1},
  primaryclass = {astro-ph.GA}
}

@article{Albareti.AllendePrieto.ea2017,
  title = {The 13th {{Data Release}} of the {{Sloan Digital Sky Survey}}: {{First Spectroscopic Data}} from the {{SDSS}}-{{IV Survey Mapping Nearby Galaxies}} at {{Apache Point Observatory}}},
  shorttitle = {The 13th {{Data Release}} of the {{Sloan Digital Sky Survey}}},
  author = {Albareti, Franco D. and Allende Prieto, Carlos and Almeida, Andres and Anders, Friedrich and Anderson, Scott and Andrews, Brett H. and {Arag{\'o}n-Salamanca}, Alfonso and {Argudo-Fern{\'a}ndez}, Maria and Armengaud, Eric and Aubourg, Eric and {Avila-Reese}, Vladimir and Badenes, Carles and Bailey, Stephen and Barbuy, Beatriz and Barger, Kat and {Barrera-Ballesteros}, Jorge and Bartosz, Curtis and Basu, Sarbani and Bates, Dominic and Battaglia, Giuseppina and Baumgarten, Falk and Baur, Julien and Bautista, Julian and Beers, Timothy C. and Belfiore, Francesco and Bershady, Matthew and {Bertran de Lis}, Sara and Bird, Jonathan C. and Bizyaev, Dmitry and Blanc, Guillermo A. and Blanton, Michael and Blomqvist, Michael and Bolton, Adam S. and Borissova, J. and Bovy, Jo and Brandt, William Nielsen and Brinkmann, Jonathan and Brownstein, Joel R. and Bundy, Kevin and Burtin, Etienne and Busca, Nicol{\'a}s G. and Orlando Camacho Chavez, Hugo and Cano D{\'i}az, M. and Cappellari, Michele and Carrera, Ricardo and Chen, Yanping and Cherinka, Brian and Cheung, Edmond and Chiappini, Cristina and Chojnowski, Drew and Chuang, Chia-Hsun and Chung, Haeun and Cirolini, Rafael Fernando and Clerc, Nicolas and Cohen, Roger E. and Comerford, Julia M. and Comparat, Johan and {Correa do Nascimento}, Janaina and Cousinou, Marie-Claude and Covey, Kevin and Crane, Jeffrey D. and Croft, Rupert and Cunha, Katia and Darling, Jeremy and Davidson, Jr., James W. and Dawson, Kyle and Da Costa, Luiz and Da Silva Ilha, Gabriele and Deconto Machado, Alice and Delubac, Timoth{\'e}e and De Lee, Nathan and {De la Macorra}, Axel and {De la Torre}, Sylvain and {Diamond-Stanic}, Aleksandar M. and Donor, John and Downes, Juan Jose and Drory, Niv and Du, Cheng and {Du Mas des Bourboux}, H{\'e}lion and Dwelly, Tom and Ebelke, Garrett and Eigenbrot, Arthur and Eisenstein, Daniel J. and Elsworth, Yvonne P. and Emsellem, Eric and Eracleous, Michael and Escoffier, Stephanie and Evans, Michael L. and {Falc{\'o}n-Barroso}, Jes{\'u}s and Fan, Xiaohui and Favole, Ginevra and {Fernandez-Alvar}, Emma and {Fernandez-Trincado}, J. G. and Feuillet, Diane and Fleming, Scott W. and {Font-Ribera}, Andreu and Freischlad, Gordon and Frinchaboy, Peter and Fu, Hai and Gao, Yang and Garcia, Rafael A. and {Garcia-Dias}, R. and {Garcia-Hern{\'a}ndez}, D. A. and Garcia P{\'e}rez, Ana E. and Gaulme, Patrick and Ge, Junqiang and Geisler, Douglas and Gillespie, Bruce and Gil Marin, Hector and Girardi, L{\'e}o and Goddard, Daniel and Gomez Maqueo Chew, Yilen and {Gonzalez-Perez}, Violeta and Grabowski, Kathleen and Green, Paul and Grier, Catherine J. and Grier, Thomas and Guo, Hong and Guy, Julien and Hagen, Alex and Hall, Matt and Harding, Paul and Harley, R. E. and Hasselquist, Sten and Hawley, Suzanne and Hayes, Christian R. and Hearty, Fred and Hekker, Saskia and Hernandez Toledo, Hector and Ho, Shirley and Hogg, David W. and {Holley-Bockelmann}, Kelly and Holtzman, Jon A. and Holzer, Parker H. and Hu, Jian and Huber, Daniel and Hutchinson, Timothy Alan and Hwang, Ho Seong and {Ibarra-Medel}, H{\'e}ctor J. and Ivans, Inese I. and Ivory, KeShawn and Jaehnig, Kurt and Jensen, Trey W. and Johnson, Jennifer A. and Jones, Amy and Jullo, Eric and Kallinger, T. and Kinemuchi, Karen and Kirkby, David and Klaene, Mark and Kneib, Jean-Paul and Kollmeier, Juna A. and Lacerna, Ivan and Lane, Richard R. and Lang, Dustin and Laurent, Pierre and Law, David R. and Leauthaud, Alexie and Le Goff, Jean-Marc and Li, Chen and Li, Cheng and Li, Niu and Li, Ran and Liang, Fu-Heng and Liang, Yu and Lima, Marcos and Lin, Lihwai and Lin, Lin and Lin, Yen-Ting and Liu, Chao and Long, Dan and Lucatello, Sara and MacDonald, Nicholas and MacLeod, Chelsea L. and Mackereth, J. Ted and Mahadevan, Suvrath and Maia, Marcio Antonio Geimba and Maiolino, Roberto and Majewski, Steven R. and Malanushenko, Olena and Malanushenko, Viktor and Mallmann, N{\'i}colas Dullius and Manchado, Arturo and Maraston, Claudia and {Marques-Chaves}, Rui and Martinez Valpuesta, Inma and Masters, Karen L. and Mathur, Savita and McGreer, Ian D. and Merloni, Andrea and Merrifield, Michael R. and M{\'e}sz{\'a}ros, Szabolcs and Meza, Andres and Miglio, Andrea and Minchev, Ivan and Molaverdikhani, Karan and {Montero-Dorta}, Antonio D. and Mosser, Benoit and Muna, Demitri and Myers, Adam and Nair, Preethi and Nandra, Kirpal and Ness, Melissa and Newman, Jeffrey A. and Nichol, Robert C. and Nidever, David L. and Nitschelm, Christian and O'Connell, Julia and Oravetz, Audrey and Oravetz, Daniel J. and Pace, Zachary and Padilla, Nelson and {Palanque-Delabrouille}, Nathalie and Pan, Kaike and Parejko, John and Paris, Isabelle and Park, Changbom and Peacock, John A. and Peirani, Sebastien and {Pellejero-Ibanez}, Marcos and Penny, Samantha and Percival, Will J. and Percival, Jeffrey W. and {Perez-Fournon}, Ismael and Petitjean, Patrick and Pieri, Matthew and Pinsonneault, Marc H. and Pisani, Alice and Prada, Francisco and Prakash, Abhishek and {Price-Jones}, Natalie and Raddick, M. Jordan and Rahman, Mubdi and Raichoor, Anand and Barboza Rembold, Sandro and Reyna, A. M. and Rich, James and Richstein, Hannah and Ridl, Jethro and Riffel, Rogemar A. and Riffel, Rog{\'e}rio and Rix, Hans-Walter and Robin, Annie C. and Rockosi, Constance M. and {Rodr{\'i}guez-Torres}, Sergio and Rodrigues, Tha{\'i}se S. and Roe, Natalie and Roman Lopes, A. and {Rom{\'a}n-Z{\'u}{\~n}iga}, Carlos and Ross, Ashley J. and Rossi, Graziano and Ruan, John and Ruggeri, Rossana and Runnoe, Jessie C. and {Salazar-Albornoz}, Salvador and Salvato, Mara and Sanchez, Sebastian F. and Sanchez, Ariel G. and {Sanchez-Gallego}, Jos{\'e} R. and Santiago, Bas{\'i}lio Xavier and Schiavon, Ricardo and Schimoia, Jaderson S. and Schlafly, Eddie and Schlegel, David J. and Schneider, Donald P. and Sch{\"o}nrich, Ralph and Schultheis, Mathias and Schwope, Axel and Seo, Hee-Jong and Serenelli, Aldo and Sesar, Branimir and Shao, Zhengyi and Shetrone, Matthew and Shull, Michael and Silva Aguirre, Victor and Skrutskie, M. F. and Slosar, An{\v z}e and Smith, Michael and Smith, Verne V. and Sobeck, Jennifer and Somers, Garrett and Souto, Diogo and Stark, David V. and Stassun, Keivan G. and Steinmetz, Matthias and Stello, Dennis and Storchi Bergmann, Thaisa and Strauss, Michael A. and Streblyanska, Alina and Stringfellow, Guy S. and Suarez, Genaro and Sun, Jing and {Taghizadeh-Popp}, Manuchehr and Tang, Baitian and Tao, Charling and Tayar, Jamie and Tembe, Mita and Thomas, Daniel and Tinker, Jeremy and Tojeiro, Rita and Tremonti, Christy and Troup, Nicholas and Trump, Jonathan R. and {Unda-Sanzana}, Eduardo and Valenzuela, O. and {Van den Bosch}, Remco and {Vargas-Maga{\~n}a}, Mariana and Vazquez, Jose Alberto and Villanova, Sandro and Vivek, M. and Vogt, Nicole and Wake, David and Walterbos, Rene and Wang, Yuting and Wang, Enci and Weaver, Benjamin Alan and Weijmans, Anne-Marie and Weinberg, David H. and Westfall, Kyle B. and Whelan, David G. and Wilcots, Eric and Wild, Vivienne and Williams, Rob A. and Wilson, John and {Wood-Vasey}, W. M. and Wylezalek, Dominika and Xiao, Ting and Yan, Renbin and Yang, Meng and Ybarra, Jason E. and Yeche, Christophe and Yuan, Fang-Ting and Zakamska, Nadia and Zamora, Olga and Zasowski, Gail and Zhang, Kai and Zhao, Cheng and Zhao, Gong-Bo and Zheng, Zheng and Zheng, Zheng and Zhou, Zhi-Min and Zhu, Guangtun and Zinn, Joel C. and Zou, Hu},
  year = {2017},
  month = dec,
  volume = {233},
  pages = {25},
  doi = {10.3847/1538-4365/aa8992},
  abstract = {The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began  observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). As well as its core program, eBOSS contains two major subprograms: the Time Domain Spectroscopic Survey (TDSS) and the SPectroscopic IDentification of ERosita Sources (SPIDERS). This paper describes the first data release from SDSS-IV, Data Release 13 (DR13). DR13 makes publicly available the first 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA. It includes new observations from eBOSS, completing the Sloan Extended QUasar, Emission-line galaxy, Luminous red galaxy Survey (SEQUELS), which also targeted variability-selected objects and X-ray-selected objects. DR13 includes new reductions of the SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification, and new reductions of the SDSS-III APOGEE-1 data, improving stellar parameters for dwarf stars and cooler stars. DR13 provides more robust and precise photometric calibrations. Value-added target catalogs relevant for eBOSS, TDSS, and SPIDERS and an updated red-clump catalog for APOGEE are also available. This paper describes the location and format of the data and provides references to important technical papers. The SDSS web site, http://www.sdss.org, provides links to the data, tutorials, examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned {$\sim$}6 yr operations of SDSS-IV.},
  journal = {ApJS},
  keywords = {atlases,catalogs,surveys}
}

@article{Anderson.Hogg.ea2018,
  ids = {Anderson.Hogg.ea2018a},
  title = {Improving {{Gaia Parallax Precision}} with a {{Data}}-Driven {{Model}} of {{Stars}}},
  author = {Anderson, Lauren and Hogg, David W. and Leistedt, Boris and {Price-Whelan}, Adrian M. and Bovy, Jo},
  year = {2018},
  month = oct,
  volume = {156},
  pages = {145},
  issn = {0004-6256},
  doi = {10.3847/1538-3881/aad7bf},
  abstract = {Converting a noisy parallax measurement into a posterior belief over distance requires inference with a prior. Usually, this prior represents beliefs about the stellar density distribution of the Milky Way. However, multiband photometry exists for a large fraction of the Gaia-TGAS Catalog and is incredibly informative about stellar distances. Here, we use 2MASS colors for 1.4 million TGAS stars to build a noise-deconvolved empirical prior distribution for stars in color-magnitude space. This model contains no knowledge of stellar astrophysics or the Milky Way but is precise because it accurately generates a large number of noisy parallax measurements under an assumption of stationarity; that is, it is capable of combining the information from many stars. We use the Extreme Deconvolution (XD) algorithm\textemdash which is an empirical-Bayes approximation to a full-hierarchical model of the true parallax and photometry of every star\textemdash to construct this prior. The prior is combined with a TGAS likelihood to infer a precise photometric-parallax estimate and uncertainty (and full posterior) for every star. Our parallax estimates are more precise than the TGAS catalog entries by a median factor of 1.2 (14\% are more precise by a factor {$>$}2) and they are more precise than the previous Bayesian distance estimates that use spatial priors. We validate our parallax inferences using members of the Milky Way star cluster M67, which is not visible as a cluster in the TGAS parallax estimates but appears as a cluster in our posterior parallax estimates. Our results, including a parallax posterior probability distribution function for each of 1.4 million TGAS stars, are available in companion electronic tables.},
  journal = {AJ},
  keywords = {catalogs,Hertzsprung–Russell and C–M diagrams,methods: statistical,parallaxes}
}

@article{Ando.Osaki1975,
  title = {Nonadiabatic Nonradial Oscillations - an Application to the Five-Minute Oscillation of the Sun},
  author = {Ando, H. and Osaki, Y.},
  year = {1975},
  volume = {27},
  pages = {581--603},
  issn = {0004-6264},
  abstract = {A solution is obtained for the equations of linear nonadiabatic  nonradial oscillations for acoustic modes trapped in the solar convection zone on the basis of a solar envelope model. The growth or damping rates of oscillations are determined from the imaginary part of eigenfrequencies. The radiative transfer of perturbations is treated by the Eddington approximation which is applicable both for the optically thick and thin cases. Results of stability analysis are shown in the diagnostic diagram and compared with the observed power spectra of the five-minute oscillation. It is found that many of the acoustic modes are overstable mainly due to the so-called Kappa-mechanism of the hydrogen ionization zone, while atmospheric radiation loss plays an important part in the stability of higher overtones. Unstable modes occupy a long mountain-range-like region in the diagnostic diagram centered with a period of 300 sec and with a wide range of wavelength.},
  journal = {PASJ},
  keywords = {Acoustic Instability,Astrophysics,Eddington Approximation,Hydrogen Ions,Magnetoacoustic Waves,Nonadiabatic Theory,Nonstabilized Oscillation,Radiative Transfer,Solar Atmosphere,Stellar Envelopes}
}

@article{Appourchaux.Antia.ea2015,
  title = {A Seismic and Gravitationally Bound Double Star Observed by {{Kepler}}. {{Implication}} for the Presence of a Convective Core},
  author = {Appourchaux, T. and Antia, H. M. and Ball, W. and Creevey, O. and Lebreton, Y. and Verma, K. and Vorontsov, S. and Campante, T. L. and Davies, G. R. and Gaulme, P. and R{\'e}gulo, C. and Horch, E. and Howell, S. and Everett, M. and Ciardi, D. and Fossati, L. and Miglio, A. and Montalb{\'a}n, J. and Chaplin, W. J. and Garc{\'i}a, R. A. and Gizon, L.},
  year = {2015},
  month = oct,
  volume = {582},
  pages = {A25},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201526610},
  abstract = {Context. Solar-like oscillations have been observed by Kepler and CoRoT  in many solar-type stars, thereby providing a way to probe stars using asteroseismology. Aims: The derivation of stellar parameters has usually been done with single stars. The aim of the paper is to derive the stellar parameters of a double-star system (HIP 93511), for which an interferometric orbit has been observed along with asteroseismic measurements. Methods: We used a time series of nearly two years of data for the double star to detect the two oscillation-mode envelopes that appear in the power spectrum. Using a new scaling relation based on luminosity, we derived the radius and mass of each star. We derived the age of each star using two proxies: one based upon the large frequency separation and a new one based upon the small frequency separation. Using stellar modelling, the mode frequencies allowed us to derive the radius, the mass, and the age of each component. In addition, speckle interferometry performed since 2006 has enabled us to recover the orbit of the system and the total mass of the system. Results: From the determination of the orbit, the total mass of the system is 2.34-0.33+0.45 M{$\odot$}. The total seismic mass using scaling relations is 2.47 {$\pm$} 0.07 M{$\odot$}. The seismic age derived using the new proxy based upon the small frequency separation is 3.5 {$\pm$} 0.3 Gyr. Based on stellar modelling, the mean common age of the system is 2.7-3.9 Gyr. The mean total seismic mass of the system is 2.34-2.53 M{$\odot$} consistent with what we determined independently with the orbit. The stellar models provide the mean radius, mass, and age of the stars as RA = 1.82-1.87R{$\odot$}, MA = 1.25-1.39 M{$\odot$}, AgeA = 2.6-3.5 Gyr; RB = 1.22-1.25 R{$\odot$}, MB = 1.08-1.14 M{$\odot$}, AgeB = 3.35-4.21 Gyr. The models provide two sets of values for Star A: [1.25-1.27] M{$\odot$} and [1.34-1.39] M{$\odot$}. We detect a convective core in Star A, while Star B does not have any. For the metallicity of the binary system of Z {$\approx$} 0.02, we set the limit between stars having a convective core in the range [1.14-1.25] M{$\odot$}. Appendices are available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {asteroseismology,astrometry,binaries: general,stars: evolution,stars: solar-type}
}

@article{Appourchaux.Chaplin.ea2012,
  title = {Oscillation Mode Frequencies of 61 Main-Sequence and Subgiant Stars Observed by {{Kepler}}},
  author = {Appourchaux, T. and Chaplin, W. J. and Garc{\'i}a, R. A. and Gruberbauer, M. and Verner, G. A. and Antia, H. M. and Benomar, O. and Campante, T. L. and Davies, G. R. and Deheuvels, S. and Handberg, R. and Hekker, S. and Howe, R. and R{\'e}gulo, C. and Salabert, D. and Bedding, T. R. and White, T. R. and Ballot, J. and Mathur, S. and Silva Aguirre, V. and Elsworth, Y. P. and Basu, S. and Gilliland, R. L. and {Christensen-Dalsgaard}, J. and Kjeldsen, H. and Uddin, K. and Stumpe, M. C. and Barclay, T.},
  year = {2012},
  month = jul,
  volume = {543},
  pages = {A54},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201218948},
  abstract = {Context. Solar-like oscillations have been observed by Kepler and CoRoT  in several solar-type stars, thereby providing a way to probe the stars using asteroseismology Aims: We provide the mode frequencies of the oscillations of various stars required to perform a comparison with those obtained from stellar modelling. Methods: We used a time series of nine months of data for each star. The 61 stars observed were categorised in three groups: simple, F-like, and mixed-mode. The simple group includes stars for which the identification of the mode degree is obvious. The F-like group includes stars for which the identification of the degree is ambiguous. The mixed-mode group includes evolved stars for which the modes do not follow the asymptotic relation of low-degree frequencies. Following this categorisation, the power spectra of the 61 main-sequence and subgiant stars were analysed using both maximum likelihood estimators and Bayesian estimators, providing individual mode characteristics such as frequencies, linewidths, and mode heights. We developed and describe a methodology for extracting a single set of mode frequencies from multiple sets derived by different methods and individual scientists. We report on how one can assess the quality of the fitted parameters using the likelihood ratio test and the posterior probabilities. Results: We provide the mode frequencies of 61 stars (with their 1-{$\sigma$} error bars), as well as their associated \'echelle diagrams. Appendices are available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {asteroseismology,stars: oscillations,stars: solar-type}
}

@inproceedings{Asplund.Grevesse.ea2005,
  title = {The Solar Chemical Composition},
  booktitle = {Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis},
  author = {Asplund, M. and Grevesse, N. and Sauval, A. J.},
  editor = {Barnes, Thomas G., III and Bash, Frank N.},
  year = {2005},
  month = sep,
  volume = {336},
  pages = {25},
  series = {Astronomical Society of the Pacific Conference Series}
}

@article{Asplund.Grevesse.ea2009,
  title = {The {{Chemical Composition}} of the {{Sun}}},
  author = {Asplund, Martin and Grevesse, Nicolas and Sauval, A. Jacques and Scott, Pat},
  year = {2009},
  month = sep,
  volume = {47},
  pages = {481--522},
  issn = {0066-4146},
  doi = {10.1146/annurev.astro.46.060407.145222},
  abstract = {The solar chemical composition is an important ingredient in our understanding of the formation, structure, and evolution of both the Sun and our Solar System. Furthermore, it is an essential reference standard against which the elemental contents of other astronomical objects are compared. In this review, we evaluate the current understanding of the solar photospheric composition. In particular, we present a redetermination of the abundances of nearly all available elements, using a realistic new three-dimensional (3D), time-dependent hydrodynamical model of the solar atmosphere. We have carefully considered the atomic input data and selection of spectral lines, and accounted for departures from local thermodynamic equilibrium (LTE) whenever possible. The end result is a comprehensive and homogeneous compilation of the solar elemental abundances. Particularly noteworthy findings are significantly lower abundances of C, N, O, and Ne compared to the widely used values of a decade ago. The new solar chemical composition is supported by a high degree of internal consistency between available abundance indicators, and by agreement with values obtained in the Solar Neighborhood and from the most pristine meteorites. There is, however, a stark conflict with standard models of the solar interior according to helioseismology, a discrepancy that has yet to find a satisfactory resolution.},
  journal = {ARA\&A}
}

@article{AstropyCollaboration.Price-Whelan.ea2018,
  title = {The {{Astropy Project}}: {{Building}} an {{Open}}-Science {{Project}} and {{Status}} of the v2.0 {{Core Package}}},
  shorttitle = {The {{Astropy Project}}},
  author = {{Astropy Collaboration} and {Price-Whelan}, A. M. and Sip{\H o}cz, B. M. and G{\"u}nther, H. M. and Lim, P. L. and Crawford, S. M. and Conseil, S. and Shupe, D. L. and Craig, M. W. and Dencheva, N. and Ginsburg, A. and VanderPlas, J. T. and Bradley, L. D. and {P{\'e}rez-Su{\'a}rez}, D. and {de Val-Borro}, M. and Aldcroft, T. L. and Cruz, K. L. and Robitaille, T. P. and Tollerud, E. J. and Ardelean, C. and Babej, T. and Bach, Y. P. and Bachetti, M. and Bakanov, A. V. and Bamford, S. P. and Barentsen, G. and Barmby, P. and Baumbach, A. and Berry, K. L. and Biscani, F. and Boquien, M. and Bostroem, K. A. and Bouma, L. G. and Brammer, G. B. and Bray, E. M. and Breytenbach, H. and Buddelmeijer, H. and Burke, D. J. and Calderone, G. and Cano Rodr{\'i}guez, J. L. and Cara, M. and Cardoso, J. V. M. and Cheedella, S. and Copin, Y. and Corrales, L. and Crichton, D. and D'Avella, D. and Deil, C. and Depagne, {\'E}. and Dietrich, J. P. and Donath, A. and Droettboom, M. and Earl, N. and Erben, T. and Fabbro, S. and Ferreira, L. A. and Finethy, T. and Fox, R. T. and Garrison, L. H. and Gibbons, S. L. J. and Goldstein, D. A. and Gommers, R. and Greco, J. P. and Greenfield, P. and Groener, A. M. and Grollier, F. and Hagen, A. and Hirst, P. and Homeier, D. and Horton, A. J. and Hosseinzadeh, G. and Hu, L. and Hunkeler, J. S. and Ivezi{\'c}, {\v Z}. and Jain, A. and Jenness, T. and Kanarek, G. and Kendrew, S. and Kern, N. S. and Kerzendorf, W. E. and Khvalko, A. and King, J. and Kirkby, D. and Kulkarni, A. M. and Kumar, A. and Lee, A. and Lenz, D. and Littlefair, S. P. and Ma, Z. and Macleod, D. M. and Mastropietro, M. and McCully, C. and Montagnac, S. and Morris, B. M. and Mueller, M. and Mumford, S. J. and Muna, D. and Murphy, N. A. and Nelson, S. and Nguyen, G. H. and Ninan, J. P. and N{\"o}the, M. and Ogaz, S. and Oh, S. and Parejko, J. K. and Parley, N. and Pascual, S. and Patil, R. and Patil, A. A. and Plunkett, A. L. and Prochaska, J. X. and Rastogi, T. and Reddy Janga, V. and Sabater, J. and Sakurikar, P. and Seifert, M. and Sherbert, L. E. and {Sherwood-Taylor}, H. and Shih, A. Y. and Sick, J. and Silbiger, M. T. and Singanamalla, S. and Singer, L. P. and Sladen, P. H. and Sooley, K. A. and Sornarajah, S. and Streicher, O. and Teuben, P. and Thomas, S. W. and Tremblay, G. R. and Turner, J. E. H. and Terr{\'o}n, V. and {van Kerkwijk}, M. H. and {de la Vega}, A. and Watkins, L. L. and Weaver, B. A. and Whitmore, J. B. and Woillez, J. and Zabalza, V. and {Astropy Contributors}},
  year = {2018},
  month = sep,
  volume = {156},
  pages = {123},
  issn = {0004-6256},
  doi = {10.3847/1538-3881/aabc4f},
  abstract = {The Astropy Project supports and fosters the development of open-source  and openly developed Python packages that provide commonly needed functionality to the astronomical community. A key element of the Astropy Project is the core package astropy, which serves as the foundation for more specialized projects and packages. In this article, we provide an overview of the organization of the Astropy project and summarize key features in the core package, as of the recent major release, version 2.0. We then describe the project infrastructure designed to facilitate and support development for a broader ecosystem of interoperable packages. We conclude with a future outlook of planned new features and directions for the broader Astropy Project. .},
  journal = {AJ},
  keywords = {astronomy,methods: data analysis,methods: miscellaneous,methods: statistical,python,reference systems}
}

@article{AstropyCollaboration.Robitaille.ea2013,
  title = {Astropy: {{A}} Community {{Python}} Package for Astronomy},
  shorttitle = {Astropy},
  author = {{Astropy Collaboration} and Robitaille, Thomas P. and Tollerud, Erik J. and Greenfield, Perry and Droettboom, Michael and Bray, Erik and Aldcroft, Tom and Davis, Matt and Ginsburg, Adam and {Price-Whelan}, Adrian M. and Kerzendorf, Wolfgang E. and Conley, Alexander and Crighton, Neil and Barbary, Kyle and Muna, Demitri and Ferguson, Henry and Grollier, Fr{\'e}d{\'e}ric and Parikh, Madhura M. and Nair, Prasanth H. and Unther, Hans M. and Deil, Christoph and Woillez, Julien and Conseil, Simon and Kramer, Roban and Turner, James E. H. and Singer, Leo and Fox, Ryan and Weaver, Benjamin A. and Zabalza, Victor and Edwards, Zachary I. and Azalee Bostroem, K. and Burke, D. J. and Casey, Andrew R. and Crawford, Steven M. and Dencheva, Nadia and Ely, Justin and Jenness, Tim and Labrie, Kathleen and Lim, Pey Lian and Pierfederici, Francesco and Pontzen, Andrew and Ptak, Andy and Refsdal, Brian and Servillat, Mathieu and Streicher, Ole},
  year = {2013},
  month = oct,
  volume = {558},
  pages = {A33},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201322068},
  abstract = {We present the first public version (v0.2) of the open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to the community, including support for domain-specific file formats such as flexible image transport system (FITS) files, Virtual Observatory (VO) tables, and common ASCII table formats, unit and physical quantity conversions, physical constants specific to astronomy, celestial coordinate and time transformations, world coordinate system (WCS) support, generalized containers for representing gridded as well as tabular data, and a framework for cosmological transformations and conversions. Significant functionality is under activedevelopment, such as a model fitting framework, VO client and server tools, and aperture and point spread function (PSF) photometry tools. The core development team is actively making additions and enhancements to the current code base, and we encourage anyone interested to participate in the development of future Astropy versions.},
  journal = {A\&A},
  keywords = {astronomy,methods: data analysis,methods: miscellaneous,python,virtual observatory tools}
}

@article{Aver.Olive.ea2015,
  title = {The Effects of {{He I}} {$\Lambda$}10830 on Helium Abundance Determinations},
  author = {Aver, Erik and Olive, Keith A. and Skillman, Evan D.},
  year = {2015},
  month = jul,
  volume = {07},
  pages = {011},
  issn = {1475-7516},
  doi = {10.1088/1475-7516/2015/07/011},
  abstract = {Observations of helium and hydrogen emission lines from metal-poor extragalactic H II regions, combined with estimates of metallicity, provide an independent method for determining the primordial helium abundance, Yp. Traditionally, the emission lines employed are in the visible wavelength range, and the number of suitable lines is limited. Furthermore, when using these lines, large systematic uncertainties in helium abundance determinations arise due to the degeneracy of physical parameters, such as temperature and density. Recently, Izotov, Thuan, \& Guseva (2014) have pioneered adding the He I {$\lambda$}10830 infrared emission line in helium abundance determinations. The strong electron density dependence of He I {$\lambda$}10830 makes it ideal for better constraining density, potentially breaking the degeneracy with temperature. We revisit our analysis of the dataset published by Izotov, Thuan, \& Stasi\&aposnska (2007) and incorporate the newly available observations of He I {$\lambda$}10830 by scaling them using the observed-to-theoretical Paschen-gamma ratio. The solutions are better constrained, in particular for electron density, temperature, and the neutral hydrogen fraction, improving the model fit to data, with the result that more spectra now pass screening for quality and reliability, in addition to a standard 95\% confidence level cut. Furthermore, the addition of He I {$\lambda$}10830 decreases the uncertainty on the helium abundance for all galaxies, with reductions in the uncertainty ranging from 10-80\%. Overall, we find a reduction in the uncertainty on Yp by over 50\%. From a regression to zero metallicity, we determine Yp = 0.2449 {$\pm$} 0.0040, consistent with the BBN result, Yp = 0.2470 {$\pm$} 0.0002, based on the Planck determination of the baryon density. The dramatic improvement in the uncertainty from incorporating He I {$\lambda$}10830 strongly supports the case for simultaneous (thus not requiring scaling) observations of visible and infrared helium emission line spectra.},
  journal = {J. Cosmol. Astropart. Phys.}
}

@inproceedings{Baglin.Auvergne.ea2006,
  title = {{{CoRoT}}: A High Precision Photometer for Stellar Ecolution and Exoplanet Finding},
  booktitle = {36th {{COSPAR}} Scientific Assembly},
  author = {Baglin, A. and Auvergne, M. and Boisnard, L. and {Lam-Trong}, T. and Barge, P. and Catala, C. and Deleuil, M. and Michel, E. and Weiss, W.},
  year = {2006},
  month = jan,
  volume = {36},
  pages = {3749},
  address = {{Beijing}, {China}}
}

@article{Bahcall.Pinsonneault.ea1995,
  title = {Solar Models with Helium and Heavy-Element Diffusion},
  author = {Bahcall, John N. and Pinsonneault, M. H. and Wasserburg, G. J.},
  year = {1995},
  month = oct,
  volume = {67},
  pages = {781--808},
  issn = {0034-6861},
  doi = {10.1103/RevModPhys.67.781},
  abstract = {Helium and heavy-element diffusion are both included in precise calculations of solar models. In addition, improvements in the input data for solar interior models are described for nuclear reaction rates, the solar luminosity, the solar age, heavy-element abundances, radiative opacities, helium and metal diffusion rates, and neutrino interaction cross sections. The effects on the neutrino fluxes of each change in the input physics are evaluated separately by constructing a series of solar models with one additional improvement added at each stage. The effective 1 {$\sigma$} uncertainties in the individual input quantities are estimated and used to evaluate the uncertainties in the calculated neutrino fluxes and the calculated event rates for solar neutrino experiments. The calculated neutrino event rates, including all of the improvements, are 9.3+1.2-1.4 SNU for the 37Cl experiment and 137+8-7 SNU for the 71Ga experiments. The calculated flux of 7Be neutrinos is 5.1 (1.00+0.06-0.07)\texttimes 109 cm-2 s-1 and the flux of 8B neutrinos is 6.6(1.00+0.14-0.17)\texttimes 106 cm-2 s-1. The primordial helium abundance found for this model is Y=0.278. The present-day surface abundance of the model is Ys=0.247, in agreement with the helioseismological measurement of Ys=0.242+/-0.003 determined by Hernandez and Christensen-Dalsgaard (1994). The computed depth of the convective zone is R=0.712Rsolar, in agreement with the observed value determined from p-mode oscillation data of R=0.713+/-0.003Rsolar found by Christensen-Dalsgaard et al. (1991). Although the present results increase the predicted event rate in the four operating solar neutrino experiments by almost 1 {$\sigma$} (theoretical uncertainty), they only slightly increase the difficulty of explaining the existing experiments with standard physics (i.e., by assuming that nothing happens to the neutrinos after they are created in the center of the sun). For an extreme model in which all diffusion (helium and heavy-element diffusion) is neglected, the event rates are 7.0+0.9-1.0 SNU for the 37Cl experiment and 126+6-6 SNU for the 71Ga experiments, while the 7Be and 8B neutrino fluxes are, respectively, 4.5(1.00+0.06-0.07)\texttimes 109 cm-2 s-1 and 4.9(1.00+0.14-0.17)\texttimes 106 cm-2 s-1. For the no-diffusion model, the computed value of the depth of the convective zone is R=0.726Rsolar, which disagrees with the observed helioseismological value. The calculated surface abundance of helium, Ys=0.268, is also in disagreement with the p-mode measurement. The authors conclude that helioseismology provides strong evidence for element diffusion and therefore for the somewhat larger solar neutrino event rates calculated in this paper.},
  journal = {Rev. Mod. Phys.}
}

@article{Bahcall.Ulrich1988,
  title = {Solar Models, Neutrino Experiments, and Helioseismology},
  author = {Bahcall, John N. and Ulrich, Roger K.},
  year = {1988},
  month = apr,
  volume = {60},
  pages = {297--372},
  issn = {0034-6861},
  doi = {10.1103/RevModPhys.60.297},
  abstract = {The event rates and their recognized uncertainties are calculated for eleven solar neutrino experiments using accurate solar models. The same solar models are used to evaluate the frequency spectrum of the p and g oscillation modes of the Sun and to compare with existing observations. A numerical table of the characteristics of the standard solar model is presented. Improved values have been calculated for all of the neutrino absorption cross sections evaluating the uncertainties for each neutrino source and detector as well as the best estimates. The neutrino capture rate calculated from the standard solar model for the 37Cl experiment is (7.91{$\pm$}0.33) SNU, which spans the total theoretical range; the rate observed by Davis and his associates is (2.0{$\pm$}0.3) SNU. The various proposed solutions to the solar neutrino problem are reviewed. A solar model is constructed with a drastically altered nuclear energy generation that eliminates entirely the important high-energy 8B and 7Be neutrinos, but which affects by less than 0.01\% the calculated p-mode oscillation frequencies.},
  journal = {Rev. Mod. Phys.},
  keywords = {Absorption Cross Sections,Computational Astrophysics,Helioseismology,Monte Carlo Method,P Waves,Solar Neutrinos,Solar Spectra,Stellar Models,Sun}
}

@article{Ball.Gizon2014,
  title = {A New Correction of Stellar Oscillation Frequencies for Near-Surface Effects},
  author = {Ball, W. H. and Gizon, L.},
  year = {2014},
  month = aug,
  volume = {568},
  pages = {A123},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201424325},
  abstract = {Context. Space-based observations of solar-like oscillations present an opportunity to constrain stellar models using individual mode frequencies. However, current stellar models are inaccurate near the surface, which introduces a systematic difference that must be corrected. Aims: We introduce and evaluate two parametrizations of the surface corrections based on formulae given by Gough (1990, LNP, 367, 283). The first we call a cubic term proportional to {$\nu$}3/ {$\mathscr{I}$} and the second has an additional inverse term proportional to {$\nu$}-1/ {$\mathscr{I}$}, where {$\nu$} and {$\mathscr{I}$} are the frequency and inertia of an oscillation mode. Methods: We first show that these formulae accurately correct model frequencies of two different solar models (Model S and a calibrated MESA model) when compared to observed BiSON frequencies. In particular, even the cubic form alone fits significantly better than a power law. We then incorporate the parametrizations into a modelling pipeline that simultaneously fits the surface effects and the underlying stellar model parameters. We apply this pipeline to synthetic observations of a Sun-like stellar model, solar observations degraded to typical asteroseismic uncertainties, and observations of the well-studied CoRoT target HD 52265. For comparison, we also run the pipeline with the scaled power-law correction proposed by Kjeldsen et al. (2008, ApJ, 683, L175). Results: The fits to synthetic and degraded solar data show that the method is unbiased and produces best-fit parameters that are consistent with the input models and known parameters of the Sun. Our results for HD 52265 are consistent with previous modelling efforts and the magnitude of the surface correction is similar to that of the Sun. The fit using a scaled power-law correction is significantly worse but yields consistent parameters, suggesting that HD 52265 is sufficiently Sun-like for the same power-law to be applicable. Conclusions: We find that the cubic term alone is suitable for asteroseismic applications and it is easy to implement in an existing pipeline. It reproduces the frequency dependence of the surface correction better than a power-law fit, both when comparing calibrated solar models to BiSON observations and when fitting stellar models using the individual frequencies. This parametrization is thus a useful new way to correct model frequencies so that observations of individual mode frequencies can be exploited.},
  journal = {A\&A},
  keywords = {asteroseismology,stars: individual: HD 52265,stars: oscillations}
}

@article{Ball.Gizon2017,
  title = {Surface-Effect Corrections for Oscillation Frequencies of Evolved Stars},
  author = {Ball, W. H. and Gizon, L.},
  year = {2017},
  month = apr,
  volume = {600},
  pages = {A128},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201630260},
  abstract = {Context. Accurate modelling of solar-like oscillators requires that modelled mode frequencies are corrected for the systematic shift caused by improper modelling of the near-surface layers, known as the surface effect. Several parametrizations of the surface effect are now available but they have not yet been systematically compared with observations of stars showing modes with mixed g- and p-mode character. Aims: We investigate how much additional uncertainty is introduced to stellar model parameters by our uncertainty about the functional form of the surface effect. At the same time, we test whether any of the parametrizations is significantly better or worse at modelling observed subgiants and low-luminosity red giants. Methods: We model six stars observed by Kepler that show clear mixed modes. We fix the input physics of the stellar models and vary the choice of surface correction between five parametrizations. Results: Models using a solar-calibrated power law correction consistently fit the observations more poorly than the other four corrections. Models with the remaining four corrections generally fit the observations about equally well, with the combined surface correction by Ball \& Gizon perhaps being marginally superior. The fits broadly agree on the model parameters within about the 2{$\sigma$} uncertainties, with discrepancies between the modified Lorentzian and free power law corrections occasionally exceeding the 3{$\sigma$} level. Relative to the best-fitting values, the total uncertainties on the masses, radii and ages of the stars are all less than 2, 1 and 6 per cent, respectively. Conclusions: A solar-calibrated power law, as formulated by Kjeldsen et al., appears unsuitable for use with more evolved solar-like oscillators. Among the remaining surface corrections, the uncertainty in the model parameters introduced by the surface effects is about twice as large as the uncertainty in the individual fits for these six stars. Though the fits are thus somewhat less certain because of our uncertainty of how to manage the surface effect, these results also demonstrate that it is feasible to model the individual mode frequencies of subgiants and low-luminosity red giants, and hence also use these individual stars to help to constrain stellar models.},
  journal = {A\&A},
  keywords = {asteroseismology,stars: oscillations}
}

@article{Balser2006,
  title = {The {{Chemical Evolution}} of {{Helium}}},
  author = {Balser, Dana S.},
  year = {2006},
  month = dec,
  volume = {132},
  pages = {2326--2332},
  issn = {0004-6256},
  doi = {10.1086/508515},
  abstract = {We report on measurements of the 4He abundance toward the outer Galaxy H II region S206 with the NRAO Green Bank Telescope. Observations of hydrogen and helium radio recombination lines between 8 and 10 GHz were made toward the peak radio continuum position in S206. We derive 4He/H=0.08459+/-0.00088 (random)+/-0.0010 (known systematic), 20\% lower than optical recombination line results. It is difficult to reconcile the large discrepancy between the optical and radio values even when accounting for temperature, density, and ionization structure or for optical extinction by dust. Using only M17 and S206 we determine {$\Delta$}Y/{$\Delta$}Z=1.41+/-0.62 in the Galaxy, consistent with standard chemical evolution models. High helium abundances in the old stellar population of elliptical galaxies can help explain the increase in UV emission with shorter wavelength between 2000 and 1200 \AA, called the ``UV upturn'' or UVX. Our lower values of {$\Delta$}Y/{$\Delta$}Z are consistent with a normal helium abundance at higher metallicity and suggest that other factors, such as a variable red giant branch mass loss with metallicity, may be important. When combined with 4He abundances in metal-poor galaxy H II regions, Magellanic Cloud H II regions, and M17 that have been determined from optical recombination lines, including the effects of temperature fluctuations, our radio 4He/H abundance ratio for S206 is consistent with a helium evolution of {$\Delta$}Y/{$\Delta$}Z=1.6. A linear extrapolation to zero metallicity predicts a 4He/H primordial abundance ratio about 5\% lower than that given by the Wilkinson Microwave Anisotropy Probe and standard big bang nucleosynthesis. The measured 4He abundances may be systematically underestimated by a few percent if clumping exists in these H II regions.},
  journal = {AJ},
  keywords = {ISM: Abundances,ISM: H II Regions,Radio Lines: ISM}
}

@article{Baraffe.Pratt.ea2017,
  title = {Lithium {{Depletion}} in {{Solar}}-like {{Stars}}: {{Effect}} of {{Overshooting Based}} on {{Realistic Multi}}-Dimensional {{Simulations}}},
  shorttitle = {Lithium {{Depletion}} in {{Solar}}-like {{Stars}}},
  author = {Baraffe, I. and Pratt, J. and Goffrey, T. and Constantino, T. and Folini, D. and Popov, M. V. and Walder, R. and Viallet, M.},
  year = {2017},
  month = aug,
  volume = {845},
  pages = {L6},
  doi = {10.3847/2041-8213/aa82ff},
  abstract = {We study lithium depletion in low-mass and solar-like stars as a  function of time, using a new diffusion coefficient describing extra-mixing taking place at the bottom of a convective envelope. This new form is motivated by multi-dimensional fully compressible, time-implicit hydrodynamic simulations performed with the MUSIC code. Intermittent convective mixing at the convective boundary in a star can be modeled using extreme value theory, a statistical analysis frequently used for finance, meteorology, and environmental science. In this Letter, we implement this statistical diffusion coefficient in a one-dimensional stellar evolution code, using parameters calibrated from multi-dimensional hydrodynamic simulations of a young low-mass star. We propose a new scenario that can explain observations of the surface abundance of lithium in the Sun and in clusters covering a wide range of ages, from {$\sim$}50 Myr to {$\sim$}4 Gyr. Because it relies on our physical model of convective penetration, this scenario has a limited number of assumptions. It can explain the observed trend between rotation and depletion, based on a single additional assumption, namely, that rotation affects the mixing efficiency at the convective boundary. We suggest the existence of a threshold in stellar rotation rate above which rotation strongly prevents the vertical penetration of plumes and below which rotation has small effects. In addition to providing a possible explanation for the long-standing problem of lithium depletion in pre-main-sequence and main-sequence stars, the strength of our scenario is that its basic assumptions can be tested by future hydrodynamic simulations.},
  journal = {Astrophys. J. Lett.},
  keywords = {convection,hydrodynamics,stars: evolution,stars: pre-main sequence,stars: rotation,stars: solar-type}
}

@article{Barber.Dobkin.ea1996,
  title = {The Quickhull Algorithm for Convex Hulls},
  author = {Barber, C. Bradford and Dobkin, David P. and Huhdanpaa, Hannu},
  year = {1996},
  month = dec,
  volume = {22},
  pages = {469--483},
  issn = {0098-3500},
  doi = {10.1145/235815.235821},
  abstract = {The convex hull of a set of points is the smallest convex set that contains the points. This article presents a practical convex hull algorithm that combines the two-dimensional Quickhull algorithm with the general-dimension Beneath-Beyond Algorithm. It is similar to the randomized, incremental algorithms for convex hull and delaunay triangulation. We provide empirical evidence that the algorithm runs faster when the input contains nonextreme points and that it used less memory. computational geometry algorithms have traditionally assumed that input sets are well behaved. When an algorithm is implemented with floating-point arithmetic, this assumption can lead to serous errors. We briefly describe a solution to this problem when computing the convex hull in two, three, or four dimensions. The output is a set of ``thick'' facets that contain all possible exact convex hulls of the input. A variation is effective in five or more dimensions.},
  journal = {ACM Trans. Math. Softw.},
  keywords = {convex hull,Delaunay triangulation,halfspace intersection,Voronoi diagram},
  number = {4}
}

@article{Basu.Antia1995,
  title = {Helium Abundance in the Solar Envelope},
  author = {Basu, Sarbani and Antia, H. M.},
  year = {1995},
  month = oct,
  volume = {276},
  pages = {1402--1408},
  doi = {10.1093/mnras/276.4.1402},
  abstract = {The abundance of helium in the solar envelope can be determined using the variation of the adiabatic index of the stellar material in the second helium ionization zone. All techniques for inferring helium abundance from the observed frequencies of solar p modes are known to be sensitive to the equation of state used in the reference models. The sensitivity of inferred helium abundance to the equation of state is studied by using different reference models with MHD and OPAL equations of state. Recent observations of high-degree solar p-mode frequencies yield a helium abundance Y=0.246 when determined using reference models with the MHD equation of state and Y=0.249 using the OPAL equation of state. Further, the models constructed with the OPAL equation of state are found to be in better agreement with the inferred sound speed below the HeII ionization zone.},
  journal = {MNRAS},
  keywords = {EQUATION OF STATE,SUN: ABUNDANCES,SUN: OSCILLATIONS}
}

@article{Basu.Antia2004,
  title = {Constraining {{Solar Abundances Using Helioseismology}}},
  author = {Basu, Sarbani and Antia, H. M.},
  year = {2004},
  month = may,
  volume = {606},
  pages = {L85-L88},
  doi = {10.1086/421110},
  abstract = {Recent analyses of solar photospheric abundances suggest that the oxygen abundance in the solar atmosphere needs to be revised downward. In this study, we investigate the consequence of this revision on helioseismic analyses of the depth of the solar convection zone and the helium abundance in the solar envelope and find no significant effect. We also find that the revised abundances along with the current OPAL opacity tables are not consistent with seismic data. A significant upward revision of the opacity tables is required to make solar models with lower oxygen abundance consistent with seismic observations.},
  journal = {Astrophys. J. Lett.},
  keywords = {Sun: Abundances,Sun: Interior,Sun: Oscillations}
}

@article{Basu.Mazumdar.ea2004,
  title = {Asteroseismic Determination of Helium Abundance in Stellar Envelopes},
  author = {Basu, Sarbani and Mazumdar, Anwesh and Antia, H. M. and Demarque, Pierre},
  year = {2004},
  month = may,
  volume = {350},
  pages = {277--286},
  doi = {10.1111/j.1365-2966.2004.07644.x},
  abstract = {Intermediate degree modes of the solar oscillations have previously been used to determine the solar helium abundance to a high degree of precision. However, we cannot expect to observe such modes in other stars. In this work we investigate whether low degree modes that should be available from space-based asteroseismology missions can be used to determine the helium abundance, Y, in stellar envelopes with sufficient precision. We find that the oscillatory signal in the frequencies caused by the depression in {$\Gamma$}1 in the second helium ionization zone can be used to determine the envelope helium abundance of low-mass main-sequence stars. For frequency errors of one part in 104, we expect errors {$\sigma$}Y in the estimated helium abundance to range from 0.03 for 0.8-Msolar stars to 0.01 for 1.2-Msolar stars. The task is more complicated in evolved stars, such as subgiants, but is still feasible if the relative errors in the frequencies are less than 10-4.},
  journal = {MNRAS},
  keywords = {stars: abundances,stars: oscillations}
}

@article{Bellinger.Angelou.ea2016,
  title = {Fundamental {{Parameters}} of {{Main}}-{{Sequence Stars}} in an {{Instant}} with {{Machine Learning}}},
  author = {Bellinger, Earl P. and Angelou, George C. and Hekker, Saskia and Basu, Sarbani and Ball, Warrick H. and Guggenberger, Elisabeth},
  year = {2016},
  month = oct,
  volume = {830},
  pages = {31},
  doi = {10.3847/0004-637X/830/1/31},
  abstract = {Owing to the remarkable photometric precision of space observatories  like Kepler, stellar and planetary systems beyond our own are now being characterized en masse for the first time. These characterizations are pivotal for endeavors such as searching for Earth-like planets and solar twins, understanding the mechanisms that govern stellar evolution, and tracing the dynamics of our Galaxy. The volume of data that is becoming available, however, brings with it the need to process this information accurately and rapidly. While existing methods can constrain fundamental stellar parameters such as ages, masses, and radii from these observations, they require substantial computational effort to do so. We develop a method based on machine learning for rapidly estimating fundamental parameters of main-sequence solar-like stars from classical and asteroseismic observations. We first demonstrate this method on a hare-and-hound exercise and then apply it to the Sun, 16 Cyg A and B, and 34 planet-hosting candidates that have been observed by the Kepler spacecraft. We find that our estimates and their associated uncertainties are comparable to the results of other methods, but with the additional benefit of being able to explore many more stellar parameters while using much less computation time. We furthermore use this method to present evidence for an empirical diffusion-mass relation. Our method is open source and freely available for the community to use.6},
  journal = {ApJ},
  keywords = {methods: statistical,stars: abundances,stars: fundamental parameters,stars: low-mass,stars: oscillations,stars: solar-type}
}

@article{Bellinger.Hekker.ea2019,
  ids = {Bellinger.Hekker.ea2019a},
  title = {Stellar Ages, Masses, and Radii from Asteroseismic Modeling Are Robust to Systematic Errors in Spectroscopy},
  author = {Bellinger, E. P. and Hekker, S. and Angelou, G. C. and Stokholm, A. and Basu, S.},
  year = {2019},
  month = feb,
  volume = {622},
  pages = {A130},
  issn = {0004-6361, 1432-0746},
  doi = {10.1051/0004-6361/201834461},
  abstract = {Methods. We used the Stellar Parameters in an Instant (SPI) pipeline to estimate the parameters of nearly 100 stars observed by Kepler and Gaia, many of which are confirmed planet hosts. We adjusted the reported spectroscopic measurements of these stars by introducing faux systematic errors and, separately, artificially increasing the reported uncertainties of the measurements, and quantified the differences in the resulting parameters. Results. We find that a systematic error of 0.1 dex in [Fe/H] translates to differences of only 4\%, 2\%, and 1\% on average in the resulting stellar ages, masses, and radii, which are well within their uncertainties ({$\sim$}11\%, 3.5\%, 1.4\%) as derived by SPI. We also find that increasing the uncertainty of [Fe/H] measurements by 0.1 dex increases the uncertainties of the ages, masses, and radii by only 0.01 Gyr, 0.02 M , and 0.01 R , which are again well below their reported uncertainties ({$\sim$}0.5 Gyr, 0.04 M , 0.02 R ). The results for Teff at 100 K are similar. Conclusions. Stellar parameters from SPI are unchanged within uncertainties by errors of up to 0.14 dex or 175 K. They are even more robust to errors in Teff than the seismic scaling relations. Consequently, the parameters for their exoplanets are also robust.},
  journal = {A\&A},
  keywords = {asteroseismology,exoplanets,planets and satellites: fundamental parameters,spectroscopy,stars: abundances,stars: evolution,stars: low-mass,stars: oscillations},
  language = {en}
}

@article{Bennett.Larson.ea2013,
  title = {Nine-Year {{Wilkinson Microwave Anisotropy Probe}} ({{WMAP}}) {{Observations}}: {{Final Maps}} and {{Results}}},
  shorttitle = {Nine-Year {{Wilkinson Microwave Anisotropy Probe}} ({{WMAP}}) {{Observations}}},
  author = {Bennett, C. L. and Larson, D. and Weiland, J. L. and Jarosik, N. and Hinshaw, G. and Odegard, N. and Smith, K. M. and Hill, R. S. and Gold, B. and Halpern, M. and Komatsu, E. and Nolta, M. R. and Page, L. and Spergel, D. N. and Wollack, E. and Dunkley, J. and Kogut, A. and Limon, M. and Meyer, S. S. and Tucker, G. S. and Wright, E. L.},
  year = {2013},
  month = oct,
  volume = {208},
  pages = {20},
  doi = {10.1088/0067-0049/208/2/20},
  abstract = {We present the final nine-year maps and basic results from the Wilkinson  Microwave Anisotropy Probe (WMAP) mission. The full nine-year analysis of the time-ordered data provides updated characterizations and calibrations of the experiment. We also provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams. Temperature and polarization sky maps are examined to separate cosmic microwave background (CMB) anisotropy from foreground emission, and both types of signals are analyzed in detail. We provide new point source catalogs as well as new diffuse and point source foreground masks. An updated template-removal process is used for cosmological analysis; new foreground fits are performed, and new foreground-reduced CMB maps are presented. We now implement an optimal C -1 weighting to compute the temperature angular power spectrum. The WMAP mission has resulted in a highly constrained {$\Lambda$}CDM cosmological model with precise and accurate parameters in agreement with a host of other cosmological measurements. When WMAP data are combined with finer scale CMB, baryon acoustic oscillation, and Hubble constant measurements, we find that big bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species (N eff = 3.84 {$\pm$} 0.40). The model fit also implies that the age of the universe is t 0 = 13.772 {$\pm$} 0.059 Gyr, and the fit Hubble constant is H 0 = 69.32 {$\pm$} 0.80 km s-1 Mpc-1. Inflation is also supported: the fluctuations are adiabatic, with Gaussian random phases; the detection of a deviation of the scalar spectral index from unity, reported earlier by the WMAP team, now has high statistical significance (ns = 0.9608 {$\pm$} 0.0080); and the universe is close to flat/Euclidean (\textbackslash Omega \_k = -0.0027\^\{+ 0.0039\}\_\{-0.0038\}). Overall, the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor of 68,000 for the standard six-parameter {$\Lambda$}CDM model, based on CMB data alone. For a model including tensors, the allowed seven-parameter volume has been reduced by a factor 117,000. Other cosmological observations are in accord with the CMB predictions, and the combined data reduces the cosmological parameter volume even further. With no significant anomalies and an adequate goodness of fit, the inflationary flat {$\Lambda$}CDM model and its precise and accurate parameters rooted in WMAP data stands as the standard model of cosmology.},
  journal = {ApJS},
  keywords = {cosmic background radiation,cosmology: observations,dark matter,early universe,instrumentation: detectors,space vehicles,space vehicles: instruments,telescopes}
}

@article{Berger.Huber.ea2018,
  title = {Revised {{Radii}} of {{{\emph{Kepler}}}} {{Stars}} and {{Planets Using}} {{{\emph{Gaia}}}} {{Data Release}} 2},
  author = {Berger, Travis A. and Huber, Daniel and Gaidos, Eric and {van Saders}, Jennifer L.},
  year = {2018},
  month = oct,
  volume = {866},
  pages = {99},
  issn = {1538-4357},
  doi = {10.3847/1538-4357/aada83},
  abstract = {One bottleneck for the exploitation of data from the Kepler mission for stellar astrophysics and exoplanet research has been the lack of precise radii and evolutionary states for most of the observed stars. We report revised radii of 177,911 Kepler stars derived by combining parallaxes from the Gaia Data Release 2 with the DR25 Kepler Stellar Properties Catalog. The median radius precision is {$\approx$}8\%, a typical improvement by a factor of 4\textendash 5 over previous estimates for typical Kepler stars. We find that {$\approx$}67\% ({$\approx$}120,000) of all Kepler targets are main-sequence stars, {$\approx$}21\% ({$\approx$}37,000) are subgiants, and {$\approx$}12\% ({$\approx$}21,000) are red giants, demonstrating that subgiant contamination is less severe than some previous estimates and that Kepler targets are mostly main-sequence stars. Using the revised stellar radii, we recalculate the radii for 2123 confirmed and 1922 candidate exoplanets. We confirm the presence of a gap in the radius distribution of small, close-in planets, but find that the gap is mostly limited to incident fluxes {$>$}200 F\AA, and its location may be at a slightly larger radius (closer to {$\approx$}2 R{$\oplus$}) when compared to previous results. Furthermore, we find several confirmed exoplanets occupying a previously described ``hot super-Earth desert'' at high irradiance, show the relation between a gas-giant planet's radius and its incident flux, and establish a bona fide sample of eight confirmed planets and 30 planet candidates with Rp {$<$} 2 R{$\oplus$} in circumstellar ``habitable zones'' (incident fluxes between 0.25 and 1.50 F\AA ). The results presented here demonstrate the potential for transformative characterization of stellar and exoplanet populations using Gaia data.},
  journal = {ApJ},
  keywords = {distances,fundamental parameters,Gaia,Kepler,parallax},
  language = {en},
  number = {2}
}

@article{Berger.Huber.ea2020,
  title = {The {{Gaia}}-{{Kepler Stellar Properties Catalog}}. {{I}}. {{Homogeneous Fundamental Properties}} for 186,301 {{Kepler Stars}}},
  author = {Berger, Travis A. and Huber, Daniel and {van Saders}, Jennifer L. and Gaidos, Eric and Tayar, Jamie and Kraus, Adam L.},
  year = {2020},
  month = jun,
  volume = {159},
  pages = {280},
  doi = {10.3847/1538-3881/159/6/280},
  abstract = {An accurate and precise Kepler Stellar Properties Catalog is essential  for the interpretation of the Kepler exoplanet survey results. Previous Kepler Stellar Properties Catalogs have focused on reporting the best-available parameters for each star, but this has required combining data from a variety of heterogeneous sources. We present the Gaia-Kepler Stellar Properties Catalog, a set of stellar properties of 186,301 Kepler stars, homogeneously derived from isochrones and broadband photometry, Gaia Data Release 2 parallaxes, and spectroscopic metallicities, where available. Our photometric effective temperatures, derived from   \$g\textbackslash,\textbackslash mathrm\{to\}\textbackslash,\{K\}\_\{s\}\$  colors, are calibrated on stars with interferometric angular diameters. Median catalog uncertainties are 112 K for   \$\{T\}\_\{\textbackslash mathrm\{eff\}\}\$ , 0.05 dex for \$\textbackslash mathrm\{log\}\textbackslash,g\$ , 4\% for   \$\{R\}\_\{\textbackslash star \}\$ , 7\% for   \$\{M\}\_\{\textbackslash star \}\$ , 13\% for   \$\{\textbackslash rho \}\_\{\textbackslash star \}\$ , 10\% for   \$\{L\}\_\{\textbackslash star \}\$ , and 56\% for stellar age. These precise constraints on stellar properties for this sample of stars will allow unprecedented investigations into trends in stellar and exoplanet properties as a function of stellar mass and age. In addition, our homogeneous parameter determinations will permit more accurate calculations of planet occurrence and trends with stellar properties.},
  journal = {AJ},
  keywords = {205,484,555,Catalogs,Exoplanet systems,Fundamental parameters of stars}
}

@article{Blanton.Bershady.ea2017,
  title = {Sloan {{Digital Sky Survey IV}}: {{Mapping}} the {{Milky Way}}, {{Nearby Galaxies}}, and the {{Distant Universe}}},
  shorttitle = {Sloan {{Digital Sky Survey IV}}},
  author = {Blanton, Michael R. and Bershady, Matthew A. and Abolfathi, Bela and Albareti, Franco D. and Allende Prieto, Carlos and Almeida, Andres and {Alonso-Garc{\'i}a}, Javier and Anders, Friedrich and Anderson, Scott F. and Andrews, Brett and {Aquino-Ort{\'i}z}, Erik and {Arag{\'o}n-Salamanca}, Alfonso and {Argudo-Fern{\'a}ndez}, Maria and Armengaud, Eric and Aubourg, Eric and {Avila-Reese}, Vladimir and Badenes, Carles and Bailey, Stephen and Barger, Kathleen A. and {Barrera-Ballesteros}, Jorge and Bartosz, Curtis and Bates, Dominic and Baumgarten, Falk and Bautista, Julian and Beaton, Rachael and Beers, Timothy C. and Belfiore, Francesco and Bender, Chad F. and Berlind, Andreas A. and Bernardi, Mariangela and Beutler, Florian and Bird, Jonathan C. and Bizyaev, Dmitry and Blanc, Guillermo A. and Blomqvist, Michael and Bolton, Adam S. and Boquien, M{\'e}d{\'e}ric and Borissova, Jura and {van den Bosch}, Remco and Bovy, Jo and Brandt, William N. and Brinkmann, Jonathan and Brownstein, Joel R. and Bundy, Kevin and Burgasser, Adam J. and Burtin, Etienne and Busca, Nicol{\'a}s G. and Cappellari, Michele and Delgado Carigi, Maria Leticia and Carlberg, Joleen K. and Carnero Rosell, Aurelio and Carrera, Ricardo and Chanover, Nancy J. and Cherinka, Brian and Cheung, Edmond and G{\'o}mez Maqueo Chew, Yilen and Chiappini, Cristina and Choi, Peter Doohyun and Chojnowski, Drew and Chuang, Chia-Hsun and Chung, Haeun and Cirolini, Rafael Fernando and Clerc, Nicolas and Cohen, Roger E. and Comparat, Johan and {da Costa}, Luiz and Cousinou, Marie-Claude and Covey, Kevin and Crane, Jeffrey D. and Croft, Rupert A. C. and {Cruz-Gonzalez}, Irene and Garrido Cuadra, Daniel and Cunha, Katia and Damke, Guillermo J. and Darling, Jeremy and Davies, Roger and Dawson, Kyle and {de la Macorra}, Axel and Dell'Agli, Flavia and De Lee, Nathan and Delubac, Timoth{\'e}e and Di Mille, Francesco and {Diamond-Stanic}, Aleks and {Cano-D{\'i}az}, Mariana and Donor, John and Downes, Juan Jos{\'e} and Drory, Niv and {du Mas des Bourboux}, H{\'e}lion and Duckworth, Christopher J. and Dwelly, Tom and Dyer, Jamie and Ebelke, Garrett and Eigenbrot, Arthur D. and Eisenstein, Daniel J. and Emsellem, Eric and Eracleous, Mike and Escoffier, Stephanie and Evans, Michael L. and Fan, Xiaohui and {Fern{\'a}ndez-Alvar}, Emma and {Fernandez-Trincado}, J. G. and Feuillet, Diane K. and Finoguenov, Alexis and Fleming, Scott W. and {Font-Ribera}, Andreu and Fredrickson, Alexander and Freischlad, Gordon and Frinchaboy, Peter M. and Fuentes, Carla E. and Galbany, Llu{\'i}s and {Garcia-Dias}, R. and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Gaulme, Patrick and Geisler, Doug and Gelfand, Joseph D. and {Gil-Mar{\'i}n}, H{\'e}ctor and Gillespie, Bruce A. and Goddard, Daniel and {Gonzalez-Perez}, Violeta and Grabowski, Kathleen and Green, Paul J. and Grier, Catherine J. and Gunn, James E. and Guo, Hong and Guy, Julien and Hagen, Alex and Hahn, ChangHoon and Hall, Matthew and Harding, Paul and Hasselquist, Sten and Hawley, Suzanne L. and Hearty, Fred and Gonzalez Hern{\'a}ndez, Jonay I. and Ho, Shirley and Hogg, David W. and {Holley-Bockelmann}, Kelly and Holtzman, Jon A. and Holzer, Parker H. and Huehnerhoff, Joseph and Hutchinson, Timothy A. and Hwang, Ho Seong and {Ibarra-Medel}, H{\'e}ctor J. and {da Silva Ilha}, Gabriele and Ivans, Inese I. and Ivory, KeShawn and Jackson, Kelly and Jensen, Trey W. and Johnson, Jennifer A. and Jones, Amy and J{\"o}nsson, Henrik and Jullo, Eric and Kamble, Vikrant and Kinemuchi, Karen and Kirkby, David and Kitaura, Francisco-Shu and Klaene, Mark and Knapp, Gillian R. and Kneib, Jean-Paul and Kollmeier, Juna A. and Lacerna, Ivan and Lane, Richard R. and Lang, Dustin and Law, David R. and Lazarz, Daniel and Lee, Youngbae and Le Goff, Jean-Marc and Liang, Fu-Heng and Li, Cheng and Li, Hongyu and Lian, Jianhui and Lima, Marcos and Lin, Lihwai and Lin, Yen-Ting and {Bertran de Lis}, Sara and Liu, Chao and {de Icaza Lizaola}, Miguel Angel C. and Long, Dan and Lucatello, Sara and Lundgren, Britt and MacDonald, Nicholas K. and Deconto Machado, Alice and MacLeod, Chelsea L. and Mahadevan, Suvrath and Geimba Maia, Marcio Antonio and Maiolino, Roberto and Majewski, Steven R. and Malanushenko, Elena and Malanushenko, Viktor and Manchado, Arturo and Mao, Shude and Maraston, Claudia and {Marques-Chaves}, Rui and Masseron, Thomas and Masters, Karen L. and McBride, Cameron K. and McDermid, Richard M. and McGrath, Brianne and McGreer, Ian D. and Medina Pe{\~n}a, Nicol{\'a}s and Melendez, Matthew and Merloni, Andrea and Merrifield, Michael R. and Meszaros, Szabolcs and Meza, Andres and Minchev, Ivan and Minniti, Dante and Miyaji, Takamitsu and More, Surhud and Mulchaey, John and {M{\"u}ller-S{\'a}nchez}, Francisco and Muna, Demitri and Munoz, Ricardo R. and Myers, Adam D. and Nair, Preethi and Nandra, Kirpal and {Correa do Nascimento}, Janaina and Negrete, Alenka and Ness, Melissa and Newman, Jeffrey A. and Nichol, Robert C. and Nidever, David L. and Nitschelm, Christian and Ntelis, Pierros and O'Connell, Julia E. and Oelkers, Ryan J. and Oravetz, Audrey and Oravetz, Daniel and Pace, Zach and Padilla, Nelson and {Palanque-Delabrouille}, Nathalie and Alonso Palicio, Pedro and Pan, Kaike and Parejko, John K. and Parikh, Taniya and P{\^a}ris, Isabelle and Park, Changbom and Patten, Alim Y. and Peirani, Sebastien and {Pellejero-Ibanez}, Marcos and Penny, Samantha and Percival, Will J. and {Perez-Fournon}, Ismael and Petitjean, Patrick and Pieri, Matthew M. and Pinsonneault, Marc and Pisani, Alice and Poleski, Rados{\l}aw and Prada, Francisco and Prakash, Abhishek and Queiroz, Anna B{\'a}rbara de Andrade and Raddick, M. Jordan and Raichoor, Anand and Barboza Rembold, Sandro and Richstein, Hannah and Riffel, Rogemar A. and Riffel, Rog{\'e}rio and Rix, Hans-Walter and Robin, Annie C. and Rockosi, Constance M. and {Rodr{\'i}guez-Torres}, Sergio and {Roman-Lopes}, A. and {Rom{\'a}n-Z{\'u}{\~n}iga}, Carlos and Rosado, Margarita and Ross, Ashley J. and Rossi, Graziano and Ruan, John and Ruggeri, Rossana and Rykoff, Eli S. and {Salazar-Albornoz}, Salvador and Salvato, Mara and S{\'a}nchez, Ariel G. and Aguado, D. S. and {S{\'a}nchez-Gallego}, Jos{\'e} R. and Santana, Felipe A. and Santiago, Bas{\'i}lio Xavier and Sayres, Conor and Schiavon, Ricardo P. and {da Silva Schimoia}, Jaderson and Schlafly, Edward F. and Schlegel, David J. and Schneider, Donald P. and Schultheis, Mathias and Schuster, William J. and Schwope, Axel and Seo, Hee-Jong and Shao, Zhengyi and Shen, Shiyin and Shetrone, Matthew and Shull, Michael and Simon, Joshua D. and Skinner, Danielle and Skrutskie, M. F. and Slosar, An{\v z}e and Smith, Verne V. and Sobeck, Jennifer S. and Sobreira, Flavia and Somers, Garrett and Souto, Diogo and Stark, David V. and Stassun, Keivan and Stauffer, Fritz and Steinmetz, Matthias and {Storchi-Bergmann}, Thaisa and Streblyanska, Alina and Stringfellow, Guy S. and Su{\'a}rez, Genaro and Sun, Jing and Suzuki, Nao and Szigeti, Laszlo and {Taghizadeh-Popp}, Manuchehr and Tang, Baitian and Tao, Charling and Tayar, Jamie and Tembe, Mita and Teske, Johanna and Thakar, Aniruddha R. and Thomas, Daniel and Thompson, Benjamin A. and Tinker, Jeremy L. and Tissera, Patricia and Tojeiro, Rita and Hernandez Toledo, Hector and {de la Torre}, Sylvain and Tremonti, Christy and Troup, Nicholas W. and Valenzuela, Octavio and Martinez Valpuesta, Inma and {Vargas-Gonz{\'a}lez}, Jaime and {Vargas-Maga{\~n}a}, Mariana and Vazquez, Jose Alberto and Villanova, Sandro and Vivek, M. and Vogt, Nicole and Wake, David and Walterbos, Rene and Wang, Yuting and Weaver, Benjamin Alan and Weijmans, Anne-Marie and Weinberg, David H. and Westfall, Kyle B. and Whelan, David G. and Wild, Vivienne and Wilson, John and {Wood-Vasey}, W. M. and Wylezalek, Dominika and Xiao, Ting and Yan, Renbin and Yang, Meng and Ybarra, Jason E. and Y{\`e}che, Christophe and Zakamska, Nadia and Zamora, Olga and Zarrouk, Pauline and Zasowski, Gail and Zhang, Kai and Zhao, Gong-Bo and Zheng, Zheng and Zheng, Zheng and Zhou, Xu and Zhou, Zhi-Min and Zhu, Guangtun B. and Zoccali, Manuela and Zou, Hu},
  year = {2017},
  month = jul,
  volume = {154},
  pages = {28},
  doi = {10.3847/1538-3881/aa7567},
  abstract = {We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project  encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z{$\sim$} 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z{$\sim$} 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.},
  journal = {AJ},
  keywords = {cosmology: observations,galaxies: general,Galaxy: general,instrumentation: spectrographs,stars: general,surveys}
}

@article{Bohm-Vitense1958,
  title = {\"Uber Die Wasserstoffkonvektionszone in Sternen Verschiedener Effektivtemperaturen Und Leuchtkr\"afte. {{Mit}} 5 Textabbildungen},
  author = {{B{\"o}hm-Vitense}, E.},
  year = {1958},
  month = jan,
  volume = {46},
  pages = {108},
  journal = {Z. F\"ur Astrophys.}
}

@article{Bonaca.Tanner.ea2012,
  title = {Calibrating {{Convective Properties}} of {{Solar}}-like {{Stars}} in the {{Kepler Field}} of {{View}}},
  author = {Bonaca, Ana and Tanner, Joel D. and Basu, Sarbani and Chaplin, William J. and Metcalfe, Travis S. and Monteiro, M{\'a}rio J. P. F. G. and Ballot, J{\'e}r{\^o}me and Bedding, Timothy R. and Bonanno, Alfio and Broomhall, Anne-Marie and Bruntt, Hans and Campante, Tiago L. and {Christensen-Dalsgaard}, J{\o}rgen and Corsaro, Enrico and Elsworth, Yvonne and Garc{\'i}a, Rafael A. and Hekker, Saskia and Karoff, Christoffer and Kjeldsen, Hans and Mathur, Savita and R{\'e}gulo, Clara and Roxburgh, Ian and Stello, Dennis and Trampedach, Regner and Barclay, Thomas and Burke, Christopher J. and Caldwell, Douglas A.},
  year = {2012},
  month = aug,
  volume = {755},
  pages = {L12},
  issn = {0004-637X},
  doi = {10.1088/2041-8205/755/1/L12},
  abstract = {Stellar models generally use simple parameterizations to treat  convection. The most widely used parameterization is the so-called mixing-length theory where the convective eddy sizes are described using a single number, {$\alpha$}, the mixing-length parameter. This is a free parameter, and the general practice is to calibrate {$\alpha$} using the known properties of the Sun and apply that to all stars. Using data from NASA's Kepler mission we show that using the solar-calibrated {$\alpha$} is not always appropriate, and that in many cases it would lead to estimates of initial helium abundances that are lower than the primordial helium abundance. Kepler data allow us to calibrate {$\alpha$} for many other stars and we show that for the sample of stars we have studied, the mixing-length parameter is generally lower than the solar value. We studied the correlation between {$\alpha$} and stellar properties, and we find that {$\alpha$} increases with metallicity. We therefore conclude that results obtained by fitting stellar models or by using population-synthesis models constructed with solar values of {$\alpha$} are likely to have large systematic errors. Our results also confirm theoretical expectations that the mixing-length parameter should vary with stellar properties.},
  journal = {Astrophys. J. Lett.},
  keywords = {stars: fundamental parameters,stars: interiors,stars: oscillations}
}

@article{Bonanno.Schlattl.ea2002,
  title = {The Age of the {{Sun}} and the Relativistic Corrections in the {{EOS}}},
  author = {Bonanno, A. and Schlattl, H. and Patern{\`o}, L.},
  year = {2002},
  month = aug,
  volume = {390},
  pages = {1115--1118},
  issn = {0004-6361},
  doi = {10.1051/0004-6361:20020749},
  abstract = {We show that the inclusion of special relativistic corrections in the revised OPAL and MHD equations of state has a significant impact on the helioseismic determination of the solar age. Models with relativistic corrections included lead to a reduction of about 0.05-0.08 ; Gyr with respect to those obtained with the old OPAL or MHD EOS. Our best-fit value is tseis = (4.57 +/- 0.11) ; Gyr which is in remarkably good agreement with the meteoritic value for the solar age. We argue that the inclusion of relativistic corrections is important for probing the evolutionary state of a star by means of the small frequency separations delta nu l,n=nu l,n-nu l+2,n-1, for spherical harmonic degrees l = 0,1 and radial order n {$>>$} l.},
  journal = {A\&A},
  keywords = {equation of state,Sun: interior,Sun: oscillations}
}

@article{Borucki.Koch.ea2010,
  title = {Kepler {{Planet}}-{{Detection Mission}}: {{Introduction}} and {{First Results}}},
  shorttitle = {Kepler {{Planet}}-{{Detection Mission}}},
  author = {Borucki, William J. and Koch, David and Basri, Gibor and Batalha, Natalie and Brown, Timothy and Caldwell, Douglas and Caldwell, John and {Christensen-Dalsgaard}, J{\o}rgen and Cochran, William D. and DeVore, Edna and Dunham, Edward W. and Dupree, Andrea K. and Gautier, Thomas N. and Geary, John C. and Gilliland, Ronald and Gould, Alan and Howell, Steve B. and Jenkins, Jon M. and Kondo, Yoji and Latham, David W. and Marcy, Geoffrey W. and Meibom, S{\o}ren and Kjeldsen, Hans and Lissauer, Jack J. and Monet, David G. and Morrison, David and Sasselov, Dimitar and Tarter, Jill and Boss, Alan and Brownlee, Don and Owen, Toby and Buzasi, Derek and Charbonneau, David and Doyle, Laurance and Fortney, Jonathan and Ford, Eric B. and Holman, Matthew J. and Seager, Sara and Steffen, Jason H. and Welsh, William F. and Rowe, Jason and Anderson, Howard and Buchhave, Lars and Ciardi, David and Walkowicz, Lucianne and Sherry, William and Horch, Elliott and Isaacson, Howard and Everett, Mark E. and Fischer, Debra and Torres, Guillermo and Johnson, John Asher and Endl, Michael and MacQueen, Phillip and Bryson, Stephen T. and Dotson, Jessie and Haas, Michael and Kolodziejczak, Jeffrey and Van Cleve, Jeffrey and Chandrasekaran, Hema and Twicken, Joseph D. and Quintana, Elisa V. and Clarke, Bruce D. and Allen, Christopher and Li, Jie and Wu, Haley and Tenenbaum, Peter and Verner, Ekaterina and Bruhweiler, Frederick and Barnes, Jason and Prsa, Andrej},
  year = {2010},
  month = feb,
  volume = {327},
  pages = {977},
  doi = {10.1126/science.1185402},
  abstract = {The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet's surface. During the first 6 weeks of observations, Kepler monitored 156,000 stars, and five new exoplanets with sizes between 0.37 and 1.6 Jupiter radii and orbital periods from 3.2 to 4.9 days were discovered. The density of the Neptune-sized Kepler-4b is similar to that of Neptune and GJ 436b, even though the irradiation level is 800,000 times higher. Kepler-7b is one of the lowest-density planets (\textasciitilde{} 0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets.},
  journal = {Science}
}

@article{Bossini.Vallenari.ea2019,
  title = {Age Determination for 269 {{{\emph{Gaia}}}} {{DR2}} Open Clusters},
  author = {Bossini, D. and Vallenari, A. and Bragaglia, A. and {Cantat-Gaudin}, T. and Sordo, R. and {Balaguer-N{\'u}{\~n}ez}, L. and Jordi, C. and Moitinho, A. and Soubiran, C. and Casamiquela, L. and Carrera, R. and Heiter, U.},
  year = {2019},
  month = mar,
  volume = {623},
  pages = {A108},
  issn = {0004-6361, 1432-0746},
  doi = {10.1051/0004-6361/201834693},
  abstract = {Context. The Gaia Second Data Release provides precise astrometry and photometry for more than 1.3 billion sources. This catalog opens a new era concerning the characterization of open clusters and test stellar models, paving the way for better understanding of the disk properties.},
  journal = {A\&A},
  keywords = {bayesian inference,cluster ages,clusters,statistics},
  language = {en}
}

@article{Bovy.Rix.ea2016,
  title = {On {{Galactic Density Modeling}} in the {{Presence}} of {{Dust Extinction}}},
  author = {Bovy, Jo and Rix, Hans-Walter and Green, Gregory M. and Schlafly, Edward F. and Finkbeiner, Douglas P.},
  year = {2016},
  month = feb,
  volume = {818},
  pages = {130},
  issn = {0004-637X},
  doi = {10.3847/0004-637X/818/2/130},
  abstract = {Inferences about the spatial density or phase-space structure of stellar populations in the Milky Way require a precise determination of the effective survey volume. The volume observed by surveys such as Gaia or near-infrared spectroscopic surveys, which have good coverage of the Galactic midplane region, is highly complex because of the abundant small-scale structure in the three-dimensional interstellar dust extinction. We introduce a novel framework for analyzing the importance of small-scale structure in the extinction. This formalism demonstrates that the spatially complex effect of extinction on the selection function of a pencil-beam or contiguous sky survey is equivalent to a low-pass filtering of the extinction-affected selection function with the smooth density field. We find that the angular resolution of current 3D extinction maps is sufficient for analyzing Gaia sub-samples of millions of stars. However, the current distance resolution is inadequate and needs to be improved by an order of magnitude, especially in the inner Galaxy. We also present a practical and efficient method for properly taking the effect of extinction into account in analyses of Galactic structure through an effective selection function. We illustrate its use with the selection function of red-clump stars in APOGEE using and comparing a variety of current 3D extinction maps.},
  journal = {ApJ},
  keywords = {dust,extinction,Galaxy: kinematics and dynamics,Galaxy: structure,methods: data analysis,stars: statistics,surveys}
}

@article{Brogaard.Bruntt.ea2011,
  title = {Age and Helium Content of the Open Cluster {{NGC}} 6791 from Multiple Eclipsing Binary Members. {{I}}. {{Measurements}}, Methods, and First Results},
  author = {Brogaard, K. and Bruntt, H. and Grundahl, F. and Clausen, J. V. and Frandsen, S. and Vandenberg, D. A. and Bedin, L. R.},
  year = {2011},
  month = jan,
  volume = {525},
  pages = {A2},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201015503},
  abstract = {Context. Models of stellar structure and evolution can be constrained by  measuring accurate parameters of detached eclipsing binaries in open clusters. Multiple binary stars provide the means to determine helium abundances in these old stellar systems, and in turn, to improve age estimates. Aims: Earlier measurements of the masses and radii of the detached eclipsing binary V20 in the open cluster NGC 6791 were accurate enough to demonstrate that there are significant differences between current stellar models. Here we improve on those results and add measurements of two additional detached eclipsing binaries, the cluster members V18 and V80. The enlarged sample sets much tighter constraints on the properties of stellar models than has hitherto been possible, thereby improving both the accuracy and precision of the cluster age.  Methods: We employed (i) high-resolution UVES spectroscopy of V18, V20 and V80 to determine their spectroscopic effective temperatures, [Fe/H] values, and spectroscopic orbital elements; and (ii) time-series photometry from the Nordic Optical Telescope to obtain the photometric elements. Results: The masses and radii of the V18 and V20 components are found to high accuracy, with errors on the masses in the range 0.27-0.36\% and errors on the radii in the range 0.61-0.92\%. V80 is found to be magnetically active, and more observations are needed to determine its parameters accurately. The metallicity of NGC 6791 is measured from disentangled spectra of the binaries and a few single stars to be [Fe/H] = +0.29 {$\pm$} 0.03 (random) {$\pm$} 0.07 (systematic). The cluster reddening and apparent distance modulus are found to be E(B-V) = 0.160{$\pm$}0.025 and (m-M)V = 13.51 {$\pm$} 0.06. A first model comparison shows that we can constrain the helium content of the NGC 6791 stars, and thus reach a more accurate age than previously possible. It may be possible to constrain additional parameters, in particular the C, N, and O abundances. This will be investigated in Paper II. Conclusions: Using multiple, detached eclipsing binaries for determining stellar cluster ages, it is now possible to constrain parameters of stellar models, notably the helium content, which were previously out of reach. By observing a suitable number of detached eclipsing binaries in several open clusters, it will be possible to calibrate the age-scale and the helium enrichment parameter {$\Delta$}Y/{$\Delta$}Z, and provide firm constraints that stellar models must reproduce. Based on observations carried out at the Nordic Optical Telescope at La Palma and ESO's VLT/UVES ESO, Paranal, Chile (75.D-0206A, 77.D-0827A, 081.D-0091).Tables 11-22 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/525/A2},
  journal = {A\&A},
  keywords = {binaries: eclipsing,binaries: spectroscopic,open clusters and associations: individual: NGC 6791,stars: evolution,techniques: photometric,techniques: spectroscopic}
}

@article{Brogaard.VandenBerg.ea2012,
  title = {Age and Helium Content of the Open Cluster {{NGC}} 6791 from Multiple Eclipsing Binary Members. {{II}}. {{Age}} Dependencies and New Insights},
  author = {Brogaard, K. and VandenBerg, D. A. and Bruntt, H. and Grundahl, F. and Frandsen, S. and Bedin, L. R. and Milone, A. P. and Dotter, A. and Feiden, G. A. and Stetson, P. B. and Sandquist, E. and Miglio, A. and Stello, D. and {Jessen-Hansen}, J.},
  year = {2012},
  month = jul,
  volume = {543},
  pages = {A106},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201219196},
  abstract = {Context. Models of stellar structure and evolution can be constrained by  measuring accurate parameters of detached eclipsing binaries in open clusters. Multiple binary stars provide the means to determine helium abundances in these old stellar systems, and in turn, to improve estimates of their age. Aims: In the first paper of this series, we demonstrated how measurements of multiple eclipsing binaries in the old open cluster NGC 6791 sets tighter constraints on the properties of stellar models than has previously been possible, thereby potentially improving both the accuracy and precision of the cluster age. Here we add additional constraints and perform an extensive model comparison to determine the best estimates of the cluster age and helium content, employing as many observational constraints as possible. Methods: We improve our photometry and correct empirically for differential reddening effects. We then perform an extensive comparison of the new colour-magnitude diagrams (CMDs) and eclipsing binary measurements to Victoria and DSEP isochrones in order to estimate cluster parameters. We also reanalyse a spectrum of the star 2-17 to improve [Fe/H] constraints. Results: We find a best estimate of the age of \textasciitilde 8.3 Gyr for NGC 6791 while demonstrating that remaining age uncertainty is dominated by uncertainties in the CNO abundances. The helium mass fraction is well constrained at Y = 0.30{$\pm$}0.01 resulting in {$\Delta$}Y/{$\Delta$}Z \textasciitilde{} 1.4 assuming that such a relation exists. During the analysis we firmly identify blue straggler stars, including the star 2-17, and find indications for the presence of their evolved counterparts. Our analysis supports the RGB mass-loss found from asteroseismology and we determine precisely the absolute mass of stars on the lower RGB, MRGB = 1.15{$\pm$}0.02 M{$\odot$}. This will be an important consistency check for the detailed asteroseismology of cluster stars. Conclusions: Using multiple, detached eclipsing binaries for determining stellar cluster ages, it is now possible to constrain parameters of stellar models, notably the helium content, which were previously out of reach. By observing a suitable number of detached eclipsing binaries in several open clusters, it will be possible to calibrate the age-scale and the helium enrichment parameter {$\Delta$} Y/{$\Delta$} Z, and provide firm constraints that stellar models must reproduce. Based on observations carried out at the Nordic Optical Telescope at La Palma and ESO's VLT/UVES ESO, Paranal, Chile (75.D-0206A, 77.D-0827A, 81.D-0091).Photometric data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/543/A106},
  journal = {A\&A},
  keywords = {binaries: eclipsing,eclipsing binaries,helium enrichment,open clusters and associations: individual: NGC 6791,stars: abundances,stars: evolution,stellar ages,techniques: photometric,techniques: spectroscopic}
}

@article{Broomhall.Chaplin.ea2011,
  title = {Solar-Cycle Variations of Large Frequency Separations of Acoustic Modes: Implications for Asteroseismology},
  shorttitle = {Solar-Cycle Variations of Large Frequency Separations of Acoustic Modes},
  author = {Broomhall, A.-M. and Chaplin, W. J. and Elsworth, Y. and New, R.},
  year = {2011},
  month = jun,
  volume = {413},
  pages = {2978--2986},
  issn = {0035-8711},
  doi = {10.1111/j.1365-2966.2011.18375.x},
  abstract = {We have studied solar-cycle changes in the large frequency separations  that can be observed in Birmingham Solar Oscillations Network (BiSON) data. The large frequency separation is often one of the first outputs from asteroseismic studies because it can help constrain stellar properties like mass and radius. We have used three methods for estimating the large separations: use of individual p-mode frequencies, computation of the autocorrelation of frequency-power spectra, and computation of the power spectrum of the power spectrum. The values of the large separations obtained by the different methods are offset from each other and have differing sensitivities to the realization noise. A simple model was used to predict solar-cycle variations in the large separations, indicating that the variations are due to the well-known solar-cycle changes to mode frequency. However, this model is only valid over a restricted frequency range. We discuss the implications of these results for asteroseismology.},
  journal = {MNRAS},
  keywords = {methods: data analysis,Sun: helioseismology,Sun: oscillations}
}

@article{Broomhall.Miglio.ea2014,
  title = {Prospects for Asteroseismic Inference on the Envelope Helium Abundance in Red Giant Stars},
  author = {Broomhall, A.-M. and Miglio, A. and Montalb{\'a}n, J. and Eggenberger, P. and Chaplin, W. J. and Elsworth, Y. and Scuflaire, R. and Ventura, P. and Verner, G. A.},
  year = {2014},
  month = may,
  volume = {440},
  pages = {1828--1843},
  doi = {10.1093/mnras/stu393},
  abstract = {Regions of rapid variation in the internal structure of a star are often  referred to as acoustic glitches since they create a characteristic periodic signature in the frequencies of p modes. Here we examine the localized disturbance arising from the helium second ionization zone in red giant branch and clump stars. More specifically, we determine how accurately and precisely the parameters of the ionization zone can be obtained from the oscillation frequencies of stellar models. We use models produced by three different generation codes that not only cover a wide range of stages of evolution along the red giant phase but also incorporate different initial helium abundances. To study the acoustic glitch caused by the second ionization zone of helium we have determined the second differences in frequencies of modes with the same angular degree, l, and then we fit the periodic function described by Houdek \& Gough to the second differences. We discuss the conditions under which such fits robustly and accurately determine the acoustic radius of the second ionization zone of helium. When the frequency of maximum amplitude of the p-mode oscillations was greater than 40 {$\mu$}Hz a robust value for the radius of the ionization zone was recovered for the majority of models. The determined radii of the ionization zones as inferred from the mode frequencies were found to be coincident with the local maximum in the first adiabatic exponent described by the models, which is associated with the outer edge of the second ionization zone of helium. Finally, we consider whether this method can be used to distinguish stars with different helium abundances. Although a definite trend in the amplitude of the signal is observed any distinction would be difficult unless the stars come from populations with vastly different helium abundances or the uncertainties associated with the fitted parameters can be reduced. However, application of our methodology could be useful for distinguishing between different populations of red giant stars in globular clusters, where distinct populations with very different helium abundances have been observed.},
  journal = {MNRAS},
  keywords = {asteroseismology,stars: abundances,stars: interiors,stars: oscillations}
}

@article{Buldgen.Salmon.ea2016,
  title = {In-Depth Study of {{16CygB}} Using Inversion Techniques},
  author = {Buldgen, G. and Salmon, S. J. A. J. and Reese, D. R. and Dupret, M. A.},
  year = {2016},
  month = dec,
  volume = {596},
  pages = {A73},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201628773},
  abstract = {Context. The 16Cyg binary system hosts the solar-like Kepler targets with the most stringent observational constraints. Indeed, we benefit from very high quality oscillation spectra, as well as spectroscopic and interferometric observations. Moreover, this system is particularly interesting since both stars are very similar in mass but the A component is orbited by a red dwarf, whereas the B component is orbited by a Jovian planet and thus could have formed a more complex planetary system. In our previous study, we showed that seismic inversions of integrated quantities could be used to constrain microscopic diffusion in the A component. In this study, we analyse the B component in the light of a more regularised inversion. Aims: We wish to analyse independently the B component of the 16Cyg binary system using the inversion of an indicator dedicated to analyse core conditions, denoted tu. Using this independent determination, we wish to analyse any differences between both stars due to the potential influence of planetary formation on stellar structure and/or their respective evolution. Methods: First, we recall the observational constraints for 16CygB and the method we used to generate reference stellar models of this star. We then describe how we improved the inversion and how this approach could be used for future targets with a sufficient number of observed frequencies. The inversion results were then used to analyse the differences between the A and B components. Results: The inversion of the tu indicator for 16CygB shows a disagreement with models including microscopic diffusion and sharing the chemical composition previously derived for 16CygA. We show that small changes in chemical composition are insufficient to solve the problem but that extra mixing can account for the differences seen between both stars. We use a parametric approach to analyse the impact of extra mixing in the form of turbulent diffusion on the behaviour of the tu values. We conclude on the necessity of further investigations using models with a physically motivated implementation of extra mixing processes including additional constraints to further improve the accuracy with which the fundamental parameters of this system are determined.},
  journal = {A\&A},
  keywords = {asteroseismology,stars: fundamental parameters,stars: interiors,stars: oscillations}
}

@article{Campante.Lund.ea2016,
  title = {Spin-{{Orbit Alignment}} of {{Exoplanet Systems}}: {{Ensemble Analysis Using Asteroseismology}}},
  shorttitle = {Spin-{{Orbit Alignment}} of {{Exoplanet Systems}}},
  author = {Campante, T. L. and Lund, M. N. and Kuszlewicz, J. S. and Davies, G. R. and Chaplin, W. J. and Albrecht, S. and Winn, J. N. and Bedding, T. R. and Benomar, O. and Bossini, D. and Handberg, R. and Santos, A. R. G. and Van Eylen, V. and Basu, S. and {Christensen-Dalsgaard}, J. and Elsworth, Y. P. and Hekker, S. and Hirano, T. and Huber, D. and Karoff, C. and Kjeldsen, H. and Lundkvist, M. S. and North, T. S. H. and Silva Aguirre, V. and Stello, D. and White, T. R.},
  year = {2016},
  month = mar,
  volume = {819},
  pages = {85},
  issn = {0004-637X},
  doi = {10.3847/0004-637X/819/1/85},
  abstract = {The angle {$\psi$} between a planet's orbital axis and the spin axis  of its parent star is an important diagnostic of planet formation, migration, and tidal evolution. We seek empirical constraints on {$\psi$} by measuring the stellar inclination Is via asteroseismology for an ensemble of 25 solar-type hosts observed with NASA's Kepler satellite. Our results for Is are consistent with alignment at the 2{$\sigma$} level for all stars in the sample, meaning that the system surrounding the red-giant star Kepler-56 remains as the only unambiguous misaligned multiple-planet system detected to date. The availability of a measurement of the projected spin-orbit angle {$\lambda$} for two of the systems allows us to estimate {$\psi$}. We find that the orbit of the hot Jupiter HAT-P-7b is likely to be retrograde (\textbackslash psi =116\textbackslash buildrel\{\textbackslash circ\}\textbackslash over\{.\} \{4\}-14.7+30.2), whereas that of Kepler-25c seems to be well aligned with the stellar spin axis (\textbackslash psi =12\textbackslash buildrel\{\textbackslash circ\}\textbackslash over\{.\} \{6\}-11.0+6.7). While the latter result is in apparent contradiction with a statement made previously in the literature that the multi-transiting system Kepler-25 is misaligned, we show that the results are consistent, given the large associated uncertainties. Finally, we perform a hierarchical Bayesian analysis based on the asteroseismic sample in order to recover the underlying distribution of {$\psi$}. The ensemble analysis suggests that the directions of the stellar spin and planetary orbital axes are correlated, as conveyed by a tendency of the host stars to display large values of inclination.},
  journal = {ApJ},
  keywords = {asteroseismology,methods: statistical,planetary systems,planets and satellites: general,stars: solar-type,techniques: photometric}
}

@article{Campante.Lund.ea2016a,
  title = {Spin-{{Orbit Alignment}} of {{Exoplanet Systems}}: {{Ensemble Analysis Using Asteroseismology}}},
  shorttitle = {Spin-{{Orbit Alignment}} of {{Exoplanet Systems}}},
  author = {Campante, T. L. and Lund, M. N. and Kuszlewicz, J. S. and Davies, G. R. and Chaplin, W. J. and Albrecht, S. and Winn, J. N. and Bedding, T. R. and Benomar, O. and Bossini, D. and Handberg, R. and Santos, A. R. G. and Van Eylen, V. and Basu, S. and {Christensen-Dalsgaard}, J. and Elsworth, Y. P. and Hekker, S. and Hirano, T. and Huber, D. and Karoff, C. and Kjeldsen, H. and Lundkvist, M. S. and North, T. S. H. and Silva Aguirre, V. and Stello, D. and White, T. R.},
  year = {2016},
  month = mar,
  volume = {819},
  pages = {85},
  doi = {10.3847/0004-637X/819/1/85},
  abstract = {The angle {$\psi$} between a planet's orbital axis and the spin axis  of its parent star is an important diagnostic of planet formation, migration, and tidal evolution. We seek empirical constraints on {$\psi$} by measuring the stellar inclination Is via asteroseismology for an ensemble of 25 solar-type hosts observed with NASA's Kepler satellite. Our results for Is are consistent with alignment at the 2{$\sigma$} level for all stars in the sample, meaning that the system surrounding the red-giant star Kepler-56 remains as the only unambiguous misaligned multiple-planet system detected to date. The availability of a measurement of the projected spin-orbit angle {$\lambda$} for two of the systems allows us to estimate {$\psi$}. We find that the orbit of the hot Jupiter HAT-P-7b is likely to be retrograde (\textbackslash psi =116\textbackslash buildrel\{\textbackslash circ\}\textbackslash over\{.\} \{4\}-14.7+30.2), whereas that of Kepler-25c seems to be well aligned with the stellar spin axis (\textbackslash psi =12\textbackslash buildrel\{\textbackslash circ\}\textbackslash over\{.\} \{6\}-11.0+6.7). While the latter result is in apparent contradiction with a statement made previously in the literature that the multi-transiting system Kepler-25 is misaligned, we show that the results are consistent, given the large associated uncertainties. Finally, we perform a hierarchical Bayesian analysis based on the asteroseismic sample in order to recover the underlying distribution of {$\psi$}. The ensemble analysis suggests that the directions of the stellar spin and planetary orbital axes are correlated, as conveyed by a tendency of the host stars to display large values of inclination.},
  journal = {ApJ},
  keywords = {asteroseismology,methods: statistical,planetary systems,planets and satellites: general,stars: solar-type,techniques: photometric}
}

@article{Casagrande.Flynn.ea2007,
  title = {The Helium Abundance and {{$\Delta$Y}}/{{$\Delta$Z}} in Lower Main-Sequence Stars},
  author = {Casagrande, Luca and Flynn, Chris and Portinari, Laura and Girardi, Leo and Jimenez, Raul},
  year = {2007},
  month = dec,
  volume = {382},
  pages = {1516--1540},
  issn = {0035-8711},
  doi = {10.1111/j.1365-2966.2007.12512.x},
  abstract = {We use nearby K dwarf stars to measure the helium-to-metal enrichment ratio {$\Delta$}Y/{$\Delta$}Z, a diagnostic of the chemical history of the solar neighbourhood. Our sample of K dwarfs has homogeneously determined effective temperatures, bolometric luminosities and metallicities, allowing us to fit each star to the appropriate stellar isochrone and determine its helium content indirectly. We use a newly computed set of Padova isochrones which cover a wide range of helium and metal content. Our theoretical isochrones have been checked against a congruous set of main-sequence binaries with accurately measured masses, to discuss and validate their range of applicability. We find that the stellar masses deduced from the isochrones are usually in excellent agreement with empirical measurements. Good agreement is also found with empirical mass-luminosity relations. Despite fitting the masses of the stars very well, we find that anomalously low helium content (lower than primordial helium) is required to fit the luminosities and temperatures of the metal-poor K dwarfs, while more conventional values of the helium content are derived for the stars around solar metallicity. We have investigated the effect of diffusion in stellar models and the assumption of local thermodynamic equilibrium (LTE) in deriving metallicities. Neither of these is able to resolve the low-helium problem alone and only marginally if the cumulated effects are included, unless we assume a mixing-length which is strongly decreasing with metallicity. Further work in stellar models is urgently needed. The helium-to-metal enrichment ratio is found to be {$\Delta$}Y/{$\Delta$}Z = 2.1 +/- 0.9 around and above solar metallicity, consistent with previous studies, whereas open problems still remain at the lowest metallicities. Finally, we determine the helium content for a set of planetary host stars.},
  journal = {MNRAS},
  keywords = {binaries: general,etc.),Hertzsprung-Russell (HR) diagram,luminosities,masses,radii,stars: abundances,stars: fundamental parameters (colours,stars: interiors,stars: late-type,temperatures}
}

@article{Casagrande.Ramirez.ea2010,
  title = {An Absolutely Calibrated {{Teff}} Scale from the Infrared Flux Method. {{Dwarfs}} and Subgiants},
  author = {Casagrande, L. and Ram{\'i}rez, I. and Mel{\'e}ndez, J. and Bessell, M. and Asplund, M.},
  year = {2010},
  month = mar,
  volume = {512},
  pages = {A54},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/200913204},
  abstract = {Various effective temperature scales have been proposed over the years.  Despite much work and the high internal precision usually achieved, systematic differences of order 100 K (or more) among various scales are still present. We present an investigation based on the infrared flux method aimed at assessing the source of such discrepancies and pin down their origin. We break the impasse among different scales by using a large set of solar twins, stars which are spectroscopically and photometrically identical to the Sun, to set the absolute zero point of the effective temperature scale to within few degrees. Our newly calibrated, accurate and precise temperature scale applies to dwarfs and subgiants, from super-solar metallicities to the most metal-poor stars currently known. At solar metallicities our results validate spectroscopic effective temperature scales, whereas for [Fe/H]{$\lnapprox$} -2.5 our temperatures are roughly 100 K hotter than those determined from model fits to the Balmer lines and 200 K hotter than those obtained from the excitation equilibrium of Fe lines. Empirical bolometric corrections and useful relations linking photometric indices to effective temperatures and angular diameters have been derived. Our results take full advantage of the high accuracy reached in absolute calibration in recent years and are further validated by interferometric angular diameters and space based spectrophotometry over a wide range of effective temperatures and metallicities. Table 8 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A54},
  journal = {A\&A},
  keywords = {infrared: stars,stars: abundances,stars: atmospheres,stars: fundamental parameters,techniques: photometric}
}

@article{Chan.Bovy2020,
  title = {The {{Gaia DR2}} Parallax Zero-Point: Hierarchical Modelling of Red Clump Stars},
  shorttitle = {The {{Gaia DR2}} Parallax Zero-Point},
  author = {Chan, Victor C. and Bovy, Jo},
  year = {2020},
  month = apr,
  volume = {493},
  pages = {4367--4381},
  issn = {0035-8711},
  doi = {10.1093/mnras/staa571},
  abstract = {The systematic offset of Gaia parallaxes has been widely reported with Gaia's second data release, and it is expected to persist in future Gaia data. In order to use Gaia parallaxes to infer distances to high precision, we develop a hierarchical probabilistic model to determine the Gaia parallax zero-point offset along with the calibration of an empirical model for luminosity of red clump stars by combining astrometric and photometric measurements. Using a cross-matched sample of red clump stars from the Apache Point Observatory Galactic Evolution Experiment and Gaia Data Release 2 (DR2), we report the parallax zero-point offset in DR2 to be {$\pi\_$}0 = -48 {$\pm$} 1 {$\mu$} as. We infer the red clump absolute magnitude to be -1.622 {$\pm$} 0.004 in Ks, 0.435 {$\pm$} 0.004 in G, -1.019 {$\pm$} 0.004 in J, and -1.516 {$\pm$} 0.004 in H. The intrinsic scatter of the red clump is {$\sim$}0.09 mag in J, H, and Ks, or {$\sim$} 0.12 mag in G. We tailor our models to accommodate more complex analyses such as investigating the variations of the parallax zero-point with each source's observed magnitude, observed colour, and sky position. In particular, we find fluctuations of the zero-point across the sky to be of order or less than a few 10s of {$\mu$} as.},
  journal = {MNRAS},
  keywords = {catalogues,methods: statistical,parallaxes,stars: distances,stars: horizontal branch,surveys}
}

@book{Chandrasekhar1939,
  title = {An Introduction to the Study of Stellar Structure},
  author = {Chandrasekhar, Subrahmanyan},
  year = {1939}
}

@article{Chaplin.Elsworth.ea2007,
  title = {Solar P-{{Mode Frequencies}} over {{Three Solar Cycles}}},
  author = {Chaplin, W. J. and Elsworth, Y. and Miller, B. A. and Verner, G. A. and New, R.},
  year = {2007},
  month = apr,
  volume = {659},
  pages = {1749--1760},
  issn = {0004-637X},
  doi = {10.1086/512543},
  abstract = {We analyze thirty years of solar oscillations data collected by the Birmingham Solar Oscillations Network (BiSON). Estimates of the mean frequency shifts of low-degree p-modes have been extracted over a period spanning solar cycles 21-23. Two methods of analysis are used to extract the frequency shifts: one method uses results on fitted frequencies of individual modes, which are then averaged to give mean frequency shifts; the other method uses cross-correlations of power frequency spectra made from subsets of the data shifted in time. The frequency shifts are correlated against six proxies of solar activity, which are sensitive to magnetic and irradiance variability at a range of locations from the photosphere to the corona. We find proxies that have good sensitivity to the effects of weak-component magnetic flux-which is more widely distributed in latitude than the strong flux in the active regions-are those that follow the frequency shifts most consistently over the three cycles. This list includes the Mg II H and K core-to-wing data, the 10.7 cm radio flux, and the He I equivalent width data. While the two methods of analysis give consistent results, use of the cross-correlation function to measure mean frequency shifts returns less precise values in cases in which the duty cycle is greater than 30\%. Estimation of uncertainties from the cross-correlation method also requires that proper allowance be made for strong correlations in the data.},
  journal = {ApJ},
  keywords = {Sun: Activity,Sun: Helioseismology,Sun: Magnetic Fields}
}

@article{Chaplin.Miglio2013,
  title = {Asteroseismology of {{Solar}}-{{Type}} and {{Red}}-{{Giant Stars}}},
  author = {Chaplin, William J. and Miglio, Andrea},
  year = {2013},
  month = aug,
  volume = {51},
  pages = {353--392},
  doi = {10.1146/annurev-astro-082812-140938},
  abstract = {We are entering a golden era for stellar physics driven by satellite and telescope observations of unprecedented quality and scope. New insights on stellar evolution and stellar interiors physics are being made possible by asteroseismology, the study of stars by the observation of natural, resonant oscillations. Asteroseismology is proving to be particularly significant for the study of solar-type and red-giant stars. These stars show rich spectra of solar-like oscillations, which are excited and intrinsically damped by turbulence in the outermost layers of the convective envelopes. In this review we discuss the current state of the field, with a particular emphasis on recent advances provided by the Kepler and COROT (Convection, Rotation \& Planetary Transits) space missions and the wider significance to astronomy of the results from asteroseismology, such as stellar populations studies and exoplanet studies.},
  journal = {ARA\&A}
}

@article{Chaplin.Serenelli.ea2020,
  title = {Age Dating of an Early {{Milky Way}} Merger via Asteroseismology of the Naked-Eye Star {$\nu$} {{Indi}}},
  author = {Chaplin, William J. and Serenelli, Aldo M. and Miglio, Andrea and Morel, Thierry and Mackereth, J. Ted and Vincenzo, Fiorenzo and Kjeldsen, Hans and Basu, Sarbani and Ball, Warrick H. and Stokholm, Amalie and Verma, Kuldeep and Mosumgaard, Jakob R{\o}rsted and Silva Aguirre, Victor and Mazumdar, Anwesh and Ranadive, Pritesh and Antia, H. M. and Lebreton, Yveline and Ong, Joel and Appourchaux, Thierry and Bedding, Timothy R. and {Christensen-Dalsgaard}, J{\o}rgen and Creevey, Orlagh and Garc{\'i}a, Rafael A. and Handberg, Rasmus and Huber, Daniel and Kawaler, Steven D. and Lund, Mikkel N. and Metcalfe, Travis S. and Stassun, Keivan G. and Bazot, Mich{\"a}el and Beck, Paul G. and Bell, Keaton J. and Bergemann, Maria and Buzasi, Derek L. and Benomar, Othman and Bossini, Diego and Bugnet, Lisa and Campante, Tiago L. and Orhan, Zeynep {\c C}elik and Corsaro, Enrico and {Gonz{\'a}lez-Cuesta}, Luc{\'i}a and Davies, Guy R. and Di Mauro, Maria Pia and Egeland, Ricky and Elsworth, Yvonne P. and Gaulme, Patrick and Ghasemi, Hamed and Guo, Zhao and Hall, Oliver J. and Hasanzadeh, Amir and Hekker, Saskia and Howe, Rachel and Jenkins, Jon M. and Jim{\'e}nez, Antonio and Kiefer, Ren{\'e} and Kuszlewicz, James S. and Kallinger, Thomas and Latham, David W. and Lundkvist, Mia S. and Mathur, Savita and Montalb{\'a}n, Josefina and Mosser, Benoit and Bed{\'o}n, Andres Moya and Nielsen, Martin Bo and {\"O}rtel, Sibel and Rendle, Ben M. and Ricker, George R. and Rodrigues, Tha{\'i}se S. and Roxburgh, Ian W. and Safari, Hossein and Schofield, Mathew and Seager, Sara and Smalley, Barry and Stello, Dennis and Szab{\'o}, R{\'o}bert and Tayar, Jamie and Theme{\ss}l, Nathalie and Thomas, Alexandra E. L. and Vanderspek, Roland K. and {van Rossem}, Walter E. and Vrard, Mathieu and Weiss, Achim and White, Timothy R. and Winn, Joshua N. and Y{\i}ld{\i}z, Mutlu},
  year = {2020},
  month = jan,
  volume = {4},
  pages = {382--389},
  issn = {2397-3366},
  doi = {10.1038/s41550-019-0975-9},
  abstract = {Over the course of its history, the Milky Way has ingested multiple  smaller satellite galaxies1. Although these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to date precisely the age at which any one merger occurred. Recent results have revealed a population of stars that were accreted via the collision of a dwarf galaxy, called Gaia-Enceladus1, leading to substantial pollution of the chemical and dynamical properties of the Milky Way. Here we identify the very bright, naked-eye star {$\nu$} Indi as an indicator of the age of the early in situ population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be 11.0 {$\pm$}0.7 ? (stat) {$\pm$}0.8 ? (sys) billion years. The star bears hallmarks consistent with having been kinematically heated by the Gaia-Enceladus collision. Its age implies that the earliest the merger could have begun was 11.6 and 13.2 billion years ago, at 68\% and 95\% confidence, respectively. Computations based on hierarchical cosmological models slightly reduce the above limits.},
  journal = {Nat. Astron.}
}

@article{Chiappini.Anders.ea2015,
  title = {Young [ {\emph{{$\alpha$}}} /{{Fe}}]-Enhanced Stars Discovered by {{CoRoT}} and {{APOGEE}}: {{What}} Is Their Origin?},
  shorttitle = {Young [ {\emph{{$\alpha$}}} /{{Fe}}]-Enhanced Stars Discovered by {{CoRoT}} and {{APOGEE}}},
  author = {Chiappini, C. and Anders, F. and Rodrigues, T. S. and Miglio, A. and Montalb{\'a}n, J. and Mosser, B. and Girardi, L. and Valentini, M. and Noels, A. and Morel, T. and Minchev, I. and Steinmetz, M. and Santiago, B. X. and Schultheis, M. and Martig, M. and {da Costa}, L. N. and Maia, M. A. G. and Allende Prieto, C. and {de Assis Peralta}, R. and Hekker, S. and Theme{\ss}l, N. and Kallinger, T. and Garc{\'i}a, R. A. and Mathur, S. and Baudin, F. and Beers, T. C. and Cunha, K. and Harding, P. and Holtzman, J. and Majewski, S. and M{\'e}sz{\'a}ros, Sz. and Nidever, D. and Pan, K. and Schiavon, R. P. and Shetrone, M. D. and Schneider, D. P. and Stassun, K.},
  year = {2015},
  month = apr,
  volume = {576},
  pages = {L12},
  issn = {0004-6361, 1432-0746},
  doi = {10.1051/0004-6361/201525865},
  abstract = {We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [{$\alpha$}/Fe] abundance ratios (as determined from APOGEE spectra) with respect to solar values. Their existence is not explained by standard chemical evolution models of the Milky Way, and shows that the chemical-enrichment history of the Galactic disc is more complex. We find similar stars in previously published samples for which isochrone-ages could be reliably obtained, although in smaller relative numbers. This might explain why these stars have not previously received attention. The young [{$\alpha$}/Fe]-rich stars are much more numerous in the CoRoT-APOGEE (CoRoGEE) inner-field sample than in any other high-resolution sample available at present because only CoRoGEE can explore the inner-disc regions and provide ages for its field stars. The kinematic properties of the young [{$\alpha$}/Fe]-rich stars are not clearly thick-disc like, despite their rather large distances from the Galactic mid-plane. Our tentative interpretation of these and previous intriguing observations in the Milky Way is that these stars were formed close to the end of the Galactic bar, near corotation \textendash{} a region where gas can be kept inert for longer times than in other regions that are more frequently shocked by the passage of spiral arms. Moreover, this is where the mass return from older inner-disc stellar generations is expected to be highest (according to an inside-out disc-formation scenario), which additionally dilutes the in-situ gas. Other possibilities to explain these observations (e.g., a recent gas-accretion event) are also discussed.},
  journal = {A\&A},
  keywords = {alpha-rich,red giants},
  language = {en}
}

@article{Chiosi.Matteucci1982,
  title = {The Helium to Heavy Element Enrichment Ratio, {{Delta Y}}/{{Delta Z}}},
  author = {Chiosi, C. and Matteucci, F. M.},
  year = {1982},
  month = jan,
  volume = {105},
  pages = {140--148},
  issn = {0004-6361},
  abstract = {The effects of mass loss by stellar wind in stars of more than one solar mass, and of different choices for the initial mass function on the helium-to-heavy element enrichment ratio, are studied on the way to the proposal of a model for the solar vicinity's chemical evolution which obeys all major observational constraints while taking account of star mass outflow and the dependence of the mass function on the gas metallicity. It is found that a Saltpeter-like mass function cannot be safely used to reproduce the observed Delta Y/Delta Z ratios unless massive star mass loss at substantial rates is invoked, since this function equally weighs both helium and metal producers. In such a case the ratio is easily matched but the observed young star metallicity and gas cannot be reproduced. It is concluded that present stellar and galactic evolution data can explain the observed Delta Y/Delta Z ratio.},
  journal = {A\&A},
  keywords = {Abundance,Astronomical Models,Chemical Evolution,Galactic Evolution,Heavy Elements,Helium,Mass Ratios,Stellar Evolution,Stellar Mass Ejection,Sun}
}

@article{Choi.Dotter.ea2016,
  title = {Mesa {{Isochrones}} and {{Stellar Tracks}} ({{MIST}}). {{I}}. {{Solar}}-Scaled {{Models}}},
  author = {Choi, Jieun and Dotter, Aaron and Conroy, Charlie and Cantiello, Matteo and Paxton, Bill and Johnson, Benjamin D.},
  year = {2016},
  month = jun,
  volume = {823},
  pages = {102},
  doi = {10.3847/0004-637X/823/2/102},
  abstract = {This is the first of a series of papers presenting the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks (MIST) project, a new comprehensive set of stellar evolutionary tracks and isochrones computed using MESA, a state-of-the-art open-source 1D stellar evolution package. In this work, we present models with solar-scaled abundance ratios covering a wide range of ages (5{$\leq$}slant \{log\}(\{Age\}) [\{year\}]{$\leq$}slant 10.3), masses (0.1{$\leq$}slant M/\{M\}{$\odot$} {$\leq$}slant 300), and metallicities (-2.0{$\leq$}slant [\{\{Z\}\}/\{\{H\}\}]{$\leq$}slant 0.5). The models are self-consistently and continuously evolved from the pre-main sequence (PMS) to the end of hydrogen burning, the white dwarf cooling sequence, or the end of carbon burning, depending on the initial mass. We also provide a grid of models evolved from the PMS to the end of core helium burning for -4.0{$\leq$}slant [\{\{Z\}\}/\{\{H\}\}]\textbackslash lt -2.0. We showcase extensive comparisons with observational constraints as well as with some of the most widely used existing models in the literature. The evolutionary tracks and isochrones can be downloaded from the project website at http://waps.cfa.harvard.edu/MIST/.},
  journal = {ApJ},
  keywords = {stars: evolution,stars: general,stars: interiors}
}

@article{Christensen-Dalsgaard.Gough1980,
  title = {Is the Sun Helium-Deficient},
  author = {{Christensen-Dalsgaard}, J. and Gough, D. O.},
  year = {1980},
  month = dec,
  volume = {288},
  pages = {544--547},
  doi = {10.1038/288544a0},
  abstract = {The recent observations of solar 5-min oscillations of low degree agree approximately with the predictions of a standard solar model with normal abundances of helium and heavy elements. Much of the apparent discrepancy noticed when the observations were first announced was a result of having neglected the influence of the sun's atmosphere in the normal mode analysis of the theoretical models. Our standard solar models are not in perfect agreement with observation, but it seems that major modifications will not be necessary to remove the remaining small discrepancies.},
  journal = {Nature},
  keywords = {Abundance,Heavy Elements,Helium,Solar Atmosphere,Solar Oscillations,Stellar Models}
}

@article{Christensen-Dalsgaard.Proffitt.ea1993,
  title = {Effects of Diffusion on Solar Models and Their Oscillation Frequencies},
  author = {{Christensen-Dalsgaard}, J. and Proffitt, C. R. and Thompson, M. J.},
  year = {1993},
  month = feb,
  volume = {403},
  pages = {L75-L78},
  doi = {10.1086/186725},
  abstract = {Settling and diffusion of helium have significant effects on the structure of solar models and their oscillation frequencies. We examine these effects in considerably more detail than has been done before, and we compare the computed frequencies with an extensive set of observed frequencies. We find that inclusion of diffusion results in a significant improvement in the agreement between theory and observations.},
  journal = {Astrophys. J. Lett.},
  keywords = {Asymptotic Properties,Frequencies,Helium,Plasma Diffusion,Solar Interior,Solar Oscillations,Stellar Models}
}

@article{Christensen-Dalsgaard1982,
  title = {Seismological Studies of the Sun and Other Stars},
  author = {{Christensen-Dalsgaard}, J.},
  year = {1982},
  volume = {2},
  pages = {11--19},
  doi = {10.1016/0273-1177(82)90250-2},
  abstract = {Aspects of solar oscillations are addressed, emphasizing their utility as probes of solar interior structure. The results of observations of solar oscillations are reviewed, and a simplified version of asymptotic analyses of these oscillations is presented. The interpretation of five-minute oscillations of high and low degree and of rotationally split modes is discussed, and the prospects for constructing a stellar seismology based on observations of five-minute oscillations and theoretical estimates of their stellar analogues using stochastic excitation are examined. Expected advances in the study of solar oscillations are discussed, mentioning the particular projects that may lead to these advances.},
  journal = {Adv. Space Res.},
  keywords = {Bibliographies,Frequencies,Periodic Variations,Seismology,Solar Interior,Solar Oscillations,Stellar Models,Stellar Oscillations,Stellar Structure}
}

@article{Christensen-Dalsgaard1984,
  title = {What {{Will Asteroseismology Teach}} Us},
  author = {{Christensen-Dalsgaard}, J.},
  year = {1984},
  pages = {11},
  abstract = {In the present paper the author considers the study of stars by means of their oscillation frequencies. Assuming high-order modes, the oscillation frequencies are conveniently discussed in terms of asymptotic theory. This is briefly reviewed. Then the author makes some remarks on observations of stellar oscillations and presents results of frequency calculations for a set of main sequence stars: such calculations are useful in giving an indication of the information that may be obtained from stellar oscillation frequencies.}
}

@article{Christensen-Dalsgaard2008,
  title = {{{ASTEC}}\textemdash the {{Aarhus STellar Evolution Code}}},
  author = {{Christensen-Dalsgaard}, J{\o}rgen},
  year = {2008},
  month = aug,
  volume = {316},
  pages = {13--24},
  doi = {10.1007/s10509-007-9675-5},
  abstract = {The Aarhus code is the result of a long development, starting in 1974, and still ongoing. A novel feature is the integration of the computation of adiabatic oscillations for specified models as part of the code. It offers substantial flexibility in terms of microphysics and has been carefully tested for the computation of solar models. However, considerable development is still required in the treatment of nuclear reactions, diffusion and convective mixing.},
  journal = {Ap\&SS}
}

@article{Clevert.Unterthiner.ea2015,
  title = {Fast and Accurate Deep Network Learning by Exponential Linear Units ({{ELUs}})},
  author = {Clevert, Djork-Arn{\'e} and Unterthiner, Thomas and Hochreiter, Sepp},
  year = {2015},
  month = nov,
  abstract = {We introduce the "exponential linear unit" (ELU) which speeds up learning in deep neural networks and leads to higher classification accuracies. Like rectified linear units (ReLUs), leaky ReLUs (LReLUs) and parametrized ReLUs (PReLUs), ELUs alleviate the vanishing gradient problem via the identity for positive values. However, ELUs have improved learning characteristics compared to the units with other activation functions. In contrast to ReLUs, ELUs have negative values which allows them to push mean unit activations closer to zero like batch normalization but with lower computational complexity. Mean shifts toward zero speed up learning by bringing the normal gradient closer to the unit natural gradient because of a reduced bias shift effect. While LReLUs and PReLUs have negative values, too, they do not ensure a noise-robust deactivation state. ELUs saturate to a negative value with smaller inputs and thereby decrease the forward propagated variation and information. Therefore, ELUs code the degree of presence of particular phenomena in the input, while they do not quantitatively model the degree of their absence. In experiments, ELUs lead not only to faster learning, but also to significantly better generalization performance than ReLUs and LReLUs on networks with more than 5 layers. On CIFAR-100 ELUs networks significantly outperform ReLU networks with batch normalization while batch normalization does not improve ELU networks. ELU networks are among the top 10 reported CIFAR-10 results and yield the best published result on CIFAR-100, without resorting to multi-view evaluation or model averaging. On ImageNet, ELU networks considerably speed up learning compared to a ReLU network with the same architecture, obtaining less than 10\% classification error for a single crop, single model network.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1511.07289},
  eprint = {1511.07289},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Computer Science - Machine Learning},
  primaryclass = {cs.LG}
}

@article{Coc.Uzan.ea2013,
  title = {Standard Big-Bang Nucleosynthesis after Planck},
  author = {Coc, Alain and Uzan, Jean-Philippe and Vangioni, Elisabeth},
  year = {2013},
  month = jul,
  abstract = {Primordial or Big Bang nucleosynthesis (BBN) is one of the three historical strong evidences for the Big-Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation (CMB). The recent results by the Planck mission have slightly changed the estimate of the baryonic density Omega\_b, compared to the previous WMAP value. This article updates the BBN predictions for the light elements using the new value of Omega\_b determined by Planck, as well as an improvement of the nuclear network and new spectroscopic observations. While there is no major modification, the error bars of the primordial D/H abundance (2.67+/-0.09) x 10\^\{-5\} are narrower and there is a slight lowering of the primordial Li/H abundance (4.89\^+0.41\_-0.39) x 10\^\{-10\}. However, this last value is still -0.5ex\textasciitilde 3 times larger than its observed spectroscopic abundance in halo stars of the Galaxy. Primordial Helium abundance is now determined to be Y\_p = 0.2463+/-0.0003.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1307.6955},
  eprint = {1307.6955},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Astrophysics - Cosmology and Extragalactic Astrophysics},
  primaryclass = {astro-ph.CO}
}

@article{Connelly.Bizzarro.ea2012,
  title = {The {{Absolute Chronology}} and {{Thermal Processing}} of {{Solids}} in the {{Solar Protoplanetary Disk}}},
  author = {Connelly, James N. and Bizzarro, Martin and Krot, Alexander N. and Nordlund, {\AA}ke and Wielandt, Daniel and Ivanova, Marina A.},
  year = {2012},
  month = nov,
  volume = {338},
  pages = {651},
  doi = {10.1126/science.1226919},
  abstract = {Transient heating events that formed calcium-aluminum-rich  inclusions (CAIs) and chondrules are fundamental processes in the evolution of the solar protoplanetary disk, but their chronology is not understood. Using U-corrected Pb-Pb dating, we determined absolute ages of individual CAIs and chondrules from primitive meteorites. CAIs define a brief formation interval corresponding to an age of 4567.30 {$\pm$} 0.16 million years (My), whereas chondrule ages range from 4567.32 {$\pm$} 0.42 to 4564.71 {$\pm$} 0.30 My. These data refute the long-held view of an age gap between CAIs and chondrules and, instead, indicate that chondrule formation started contemporaneously with CAIs and lasted \textasciitilde 3 My. This time scale is similar to disk lifetimes inferred from astronomical observations, suggesting that the formation of CAIs and chondrules reflects a process intrinsically linked to the secular evolution of accretionary disks.},
  journal = {Science}
}

@article{Cooke.Fumagalli2018,
  title = {Measurement of the Primordial Helium Abundance from the Intergalactic Medium},
  author = {Cooke, Ryan J. and Fumagalli, Michele},
  year = {2018},
  month = oct,
  volume = {2},
  pages = {957--961},
  issn = {2397-3366},
  doi = {10.1038/s41550-018-0584-z},
  abstract = {Almost every helium atom in the Universe was created just a few minutes after the Big Bang through a process commonly referred to as Big Bang nucleosynthesis1,2. The amount of helium that was made during Big Bang nucleosynthesis is determined by combining particle physics and cosmology3. The current leading measures of the primordial helium abundance (YP) are based on the relative strengths of H uc(i) and He uc(i) emission lines emanating from star-forming regions in local metal-poor galaxies4-7. As the statistical errors on these measurements improve, it is essential to test for systematics by developing independent techniques. Here we report a determination of the primordial helium abundance based on a near-pristine intergalactic gas cloud that is seen in absorption against the light of a background quasar. This gas cloud, observed when the Universe was just one-third of its present age (zabs = 1.724), has a metal content around 100 times less than that of the Sun, and at least 30\% less metal content than the most metal-poor H uc(ii) region currently known where a determination of the primordial helium abundance is possible. We conclude that the helium abundance of this intergalactic gas cloud is Y =0.25 0-0.025+0.033 , which agrees with the standard model primordial value8-10, YP = 0.24672 {$\pm$} 0.00017. Our determination of the primordial helium abundance is not yet as precise as that derived using metal-poor galaxies, but our method has the potential to offer a competitive test of physics beyond the standard model during Big Bang nucleosynthesis.},
  journal = {Nat. Astron.}
}

@article{Corsaro.DeRidder.ea2015,
  title = {High-Precision Acoustic Helium Signatures in 18 Low-Mass Low-Luminosity Red Giants: {{Analysis}} from More than Four Years of {{{\emph{Kepler}}}} Observations{$\star$}},
  shorttitle = {High-Precision Acoustic Helium Signatures in 18 Low-Mass Low-Luminosity Red Giants},
  author = {Corsaro, E. and De Ridder, J. and Garc{\'i}a, R. A.},
  year = {2015},
  month = jun,
  volume = {578},
  pages = {A76},
  issn = {0004-6361, 1432-0746},
  doi = {10.1051/0004-6361/201525922},
  abstract = {Context. High-precision frequencies of acoustic modes in red giant stars are now available thanks to the long observing length and high quality of the light curves provided by the NASA Kepler mission, thus allowing the interior of evolved cool low-mass stars to be probed with an unprecedented level of detail.},
  journal = {A\&A},
  keywords = {asteroseismology,helium,statistics},
  language = {en}
}

@book{Cox.Giuli1968,
  title = {Principles of Stellar Structure},
  author = {Cox, J. P. and Giuli, R. T.},
  year = {1968}
}

@article{Cyburt.Fields.ea2016,
  title = {Big Bang Nucleosynthesis: {{Present}} Status},
  shorttitle = {Big Bang Nucleosynthesis},
  author = {Cyburt, Richard H. and Fields, Brian D. and Olive, Keith A. and Yeh, Tsung-Han},
  year = {2016},
  month = jan,
  volume = {88},
  pages = {015004},
  issn = {0034-6861},
  doi = {10.1103/RevModPhys.88.015004},
  abstract = {Big bang nucleosynthesis (BBN) describes the production of the lightest nuclides via a dynamic interplay among the four fundamental forces during the first seconds of cosmic time. A brief overview of the essentials of this physics is given, and new calculations presented of light-element abundances through 6Li and 7Li, with updated nuclear reactions and uncertainties including those in the neutron lifetime. Fits are provided for these results as a function of baryon density and of the number of neutrino flavors N{$\nu$}. Recent developments are reviewed in BBN, particularly new, precision Planck cosmic microwave background (CMB) measurements that now probe the baryon density, helium content, and the effective number of degrees of freedom Neff. These measurements allow for a tight test of BBN and cosmology using CMB data alone. Our likelihood analysis convolves the 2015 Planck data chains with our BBN output and observational data. Adding astronomical measurements of light elements strengthens the power of BBN. A new determination of the primordial helium abundance is included in our likelihood analysis. New D/H observations are now more precise than the corresponding theoretical predictions and are consistent with the standard model and the Planck baryon density. Moreover, D/H now provides a tight measurement of N{$\nu$} when combined with the CMB baryon density and provides a 2 {$\sigma$} upper limit N{$\nu<$}3.2 . The new precision of the CMB and D/H observations together leaves D/H predictions as the largest source of uncertainties. Future improvement in BBN calculations will therefore rely on improved nuclear cross-section data. In contrast with D/H and 4He, 7Li predictions continue to disagree with observations, perhaps pointing to new physics. This paper concludes with a look at future directions including key nuclear reactions, astronomical observations, and theoretical issues.},
  journal = {Rev. Mod. Phys.}
}

@article{Das.Sanders2019,
  title = {{{MADE}}: A Spectroscopic Mass, Age, and Distance Estimator for Red Giant Stars with {{Bayesian}} Machine Learning},
  shorttitle = {{{MADE}}},
  author = {Das, Payel and Sanders, Jason L.},
  year = {2019},
  month = mar,
  volume = {484},
  pages = {294},
  doi = {10.1093/mnras/sty2776},
  abstract = {We present a new approach (MADE) that generates mass, age, and distance estimates of red giant stars from a combination of astrometric, photometric, and spectroscopic data. The core of the approach is a Bayesian artificial neural network (ANN) that learns from and completely replaces stellar isochrones. The ANN is trained using a sample of red giant stars with mass estimates from asteroseismology. A Bayesian isochrone pipeline uses the astrometric, photometric, spectroscopic, and asteroseismology data to determine posterior distributions for the training outputs: mass, age, and distance. Given new inputs, posterior predictive distributions for the outputs are computed, taking into account both input uncertainties, and uncertainties in the ANN parameters. We apply MADE to 10 000 red giants in the overlap between the 14th data release from the APO Galactic Evolution Experiment (APOGEE) and the Tycho-Gaia astrometric solution (TGAS). The ANN is able to reduce the uncertainty on mass, age, and distance estimates for training-set stars with high output uncertainties allocated through the Bayesian isochrone pipeline. The fractional uncertainties on mass are \&lt; 10 per cent and on age are between 10 to 25 per cent. Moreover, the time taken for our ANN to predict masses, ages, and distances for the entire catalogue of APOGEE-TGAS stars is of a similar order of the time taken by the Bayesian isochrone pipeline to run on a handful of stars. Our resulting catalogue clearly demonstrates the expected thick- and thin-disc components in the [M/H]-[{$\alpha$}/M] plane, when examined by age.},
  journal = {MNRAS},
  keywords = {asteroseismology,machine learning,neural network,red giants,spectroscopy},
  language = {en}
}

@article{Davies.SilvaAguirre.ea2016,
  title = {Oscillation Frequencies for 35 {{{\emph{Kepler}}}} Solar-Type Planet-Hosting Stars Using {{Bayesian}} Techniques and Machine Learning},
  author = {Davies, G. R. and Silva Aguirre, V. and Bedding, T. R. and Handberg, R. and Lund, M. N. and Chaplin, W. J. and Huber, D. and White, T. R. and Benomar, O. and Hekker, S. and Basu, S. and Campante, T. L. and {Christensen-Dalsgaard}, J. and Elsworth, Y. and Karoff, C. and Kjeldsen, H. and Lundkvist, M. S. and Metcalfe, T. S. and Stello, D.},
  year = {2016},
  month = feb,
  journal = {\mnras},
  volume = {456},
  number = {2},
  pages = {2183--2195},
  issn = {0035-8711, 1365-2966},
  doi = {10.1093/mnras/stv2593},
  urldate = {2019-10-15},
  abstract = {Kepler has revolutionized our understanding of both exoplanets and their host stars. Asteroseismology is a valuable tool in the characterization of stars and Kepler is an excellent observing facility to perform asteroseismology. Here we select a sample of 35 Kepler solar-type stars which host transiting exoplanets (or planet candidates) with detected solar-like oscillations. Using available Kepler short cadence data up to Quarter 16 we create power spectra optimized for asteroseismology of solar-type stars. We identify modes of oscillation and estimate mode frequencies by `peak bagging' using a Bayesian Markov Chain Monte Carlo framework. In addition, we expand the methodology of quality assurance using a Bayesian unsupervised machine learning approach. We report the measured frequencies of the modes of oscillation for all 35 stars and frequency ratios commonly used in detailed asteroseismic modelling. Due to the high correlations associated with frequency ratios we report the covariance matrix of all frequencies measured and frequency ratios calculated. These frequencies, frequency ratios, and covariance matrices can be used to obtain tight constraint on the fundamental parameters of these planet-hosting stars.},
  langid = {english},
  keywords = {asteroseismology,planetary systems,planets and satellites: fundamental parameters,stars: evolution,stars: fundamental parameters,stars: oscillations}
}

@article{Davies.Chaplin.ea2015,
  title = {Asteroseismic Inference on Rotation, Gyrochronology and Planetary System Dynamics of 16 {{Cygni}}},
  author = {Davies, G. R. and Chaplin, W. J. and Farr, W. M. and Garc{\'i}a, R. A. and Lund, M. N. and Mathis, S. and Metcalfe, T. S. and Appourchaux, T. and Basu, S. and Benomar, O. and Campante, T. L. and Ceillier, T. and Elsworth, Y. and Handberg, R. and Salabert, D. and Stello, D.},
  year = {2015},
  month = jan,
  volume = {446},
  pages = {2959--2966},
  issn = {0035-8711},
  doi = {10.1093/mnras/stu2331},
  abstract = {The solar analogues 16 Cyg A and B are excellent asteroseismic targets  in the Kepler field of view and together with a red dwarf and a Jovian planet form an interesting system. For these more evolved Sun-like stars we cannot detect surface rotation with the current Kepler data but instead use the technique of asteroseimology to determine rotational properties of both 16 Cyg A and B. We find the rotation periods to be 23.8\^\{+1.5\}\_\{-1.8\} and 23.2\^\{+11.5\}\_\{-3.2\} d, and the angles of inclination to be 56\^\{+6\}\_\{-5\}\textdegree{} and 36\^\{+17\}\_\{-7\}\textdegree, for A and B, respectively. Together with these results we use the published mass and age to suggest that, under the assumption of a solar-like rotation profile, 16 Cyg A could be used when calibrating gyrochronology relations. In addition, we discuss the known 16 Cyg B star-planet eccentricity and measured low obliquity which is consistent with Kozai cycling and tidal theory.},
  journal = {MNRAS},
  keywords = {asteroseismology,planet-star interactions,stars: oscillations,stars: rotation,stellar rotation}
}

@article{Davies.Miglio2016,
  title = {Asteroseismology of Red Giants: {{From}} Analysing Light Curves to Estimating Ages},
  shorttitle = {Asteroseismology of Red Giants},
  author = {Davies, G. R. and Miglio, A.},
  year = {2016},
  month = sep,
  volume = {337},
  pages = {774},
  issn = {0004-6337},
  doi = {10.1002/asna.201612371},
  abstract = {Asteroseismology has started to provide constraints on stellar properties that will be essential to accurately reconstruct the history of the Milky Way. Here we look at the information content in data sets representing current and future space missions (CoRoT, Kepler, K2, TESS, and PLATO) for red giant stars. We describe techniques for extracting the information in the frequency power spectrum and apply these techniques to Kepler data sets of different observing length to represent the different space missions. We demonstrate that for KIC 12008916, a low-luminosity red giant branch star, we can extract useful information from all data sets, and for all but the shortest data set we obtain good constraint on the g-mode period spacing and core rotation rates. We discuss how the high precision in these parameters will constrain the stellar properties of stellar radius, distance, mass and age. We show that high precision can be achieved in mass and hence age when values of the g-mode period spacing are available. We caution that tests to establish the accuracy of asteroseismic masses and ages are still ``work in progress''.},
  journal = {Astron. Nachrichten},
  keywords = {ages,analysis,asteroseismology,red giants,stars: fundamental parameters,stars: individual (KIC 12008916),stars: interiors,stars: oscillations}
}

@article{Deubner.Gough1984,
  title = {Helioseismology: {{Oscillations}} as a {{Diagnostic}} of the {{Solar Interior}}},
  shorttitle = {Helioseismology},
  author = {Deubner, Franz-Ludwig and Gough, Douglas},
  year = {1984},
  volume = {22},
  pages = {593--619},
  doi = {10.1146/annurev.aa.22.090184.003113},
  abstract = {Contents: (1) Introduction. (2) Resonant cavities in the Sun. (3) Observational methods. (4) High-degree modes: Solar structure. Subphotospheric velocities. (5) Low-degree modes: High-order p modes. Gravity modes. Solar structure. (6) Five-minute modes of intermediate degree. (7) Limb observations. (8) Problems for the immediate future. Appendix: Classification of stellar oscillations.},
  journal = {ARA\&A}
}

@article{Deubner.Ulrich.ea1979,
  title = {Solar P-Mode Oscillations as a Tracer of Radial Differential Rotation},
  author = {Deubner, F.-L. and Ulrich, R. K. and Rhodes, Jr., E. J.},
  year = {1979},
  month = feb,
  volume = {72},
  pages = {177--185},
  issn = {0004-6361},
  abstract = {Photoelectric observations of solar p-modes obtained with improved wavenumber and frequency resolution are presented. The observations are compared with model calculations of the p-modes, and the degree of spatial and temporal coherence of the observed wave pattern is investigated. It is found that the p-mode oscillations pervade the visible surface of the sun with a high degree of coherence in space and time, so that the whole complex pattern of standing waves with its nodes and antinodes can be regarded as a fixed pattern corotating with the solar surface layers. The p-modes are introduced as a tracer of solar rotational flow velocities. The equatorial differential rotation is estimated as a function of effective depth on the basis of the theoretical contribution functions for the p-modes recently derived by Ulrich et al. (1978). The results strongly indicate that the angular speed of rotation is not uniform even in the relatively shallow layer extending about 20,000 km below the photosphere.},
  journal = {A\&A},
  keywords = {Angular Velocity,Atmospheric Models,Chromosphere,Flow Velocity,Solar Oscillations,Solar Rotation,Standing Waves,Vibration Mode}
}

@article{Dillon.Langmore.ea2017,
  ids = {Dillon.Langmore.ea2017a},
  title = {{{TensorFlow Distributions}}},
  author = {Dillon, Joshua V. and Langmore, Ian and Tran, Dustin and Brevdo, Eugene and Vasudevan, Srinivas and Moore, Dave and Patton, Brian and Alemi, Alex and Hoffman, Matt and Saurous, Rif A.},
  year = {2017},
  month = nov,
  abstract = {The TensorFlow Distributions library implements a vision of probability theory adapted to the modern deep-learning paradigm of end-to-end differentiable computation. Building on two basic abstractions, it offers flexible building blocks for probabilistic computation. Distributions provide fast, numerically stable methods for generating samples and computing statistics, e.g., log density. Bijectors provide composable volume-tracking transformations with automatic caching. Together these enable modular construction of high dimensional distributions and transformations not possible with previous libraries (e.g., pixelCNNs, autoregressive flows, and reversible residual networks). They are the workhorse behind deep probabilistic programming systems like Edward and empower fast black-box inference in probabilistic models built on deep-network components. TensorFlow Distributions has proven an important part of the TensorFlow toolkit within Google and in the broader deep learning community.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1711.10604},
  eprint = {1711.10604},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Computer Science - Artificial Intelligence,Computer Science - Machine Learning,Computer Science - Programming Languages,Statistics - Machine Learning},
  primaryclass = {cs.LG}
}

@article{Dotter.Conroy.ea2017,
  title = {The {{Influence}} of {{Atomic Diffusion}} on {{Stellar Ages}} and {{Chemical Tagging}}},
  author = {Dotter, Aaron and Conroy, Charlie and Cargile, Phillip and Asplund, Martin},
  year = {2017},
  month = may,
  volume = {840},
  pages = {99},
  doi = {10.3847/1538-4357/aa6d10},
  abstract = {In the era of large stellar spectroscopic surveys, there is an emphasis on deriving not only stellar abundances but also the ages for millions of stars. In the context of Galactic archeology, stellar ages provide a direct probe of the formation history of the Galaxy. We use the stellar evolution code MESA to compute models with atomic diffusion\textemdash with and without radiative acceleration\textemdash and extra mixing in the surface layers. The extra mixing consists of both density-dependent turbulent mixing and envelope overshoot mixing. Based on these models we argue that it is important to distinguish between initial, bulk abundances (parameters) and current, surface abundances (variables) in the analysis of individual stellar ages. In stars that maintain radiative regions on evolutionary timescales, atomic diffusion modifies the surface abundances. We show that when initial, bulk metallicity is equated with current, surface metallicity in isochrone age analysis, the resulting stellar ages can be systematically overestimated by up to 20\%. The change of surface abundances with evolutionary phase also complicates chemical tagging, which is the concept that dispersed star clusters can be identified through unique, high-dimensional chemical signatures. Stars from the same cluster, but in different evolutionary phases, will show different surface abundances. We speculate that calibration of stellar models may allow us to estimate not only stellar ages but also initial abundances for individual stars. In the meantime, analyzing the chemical properties of stars in similar evolutionary phases is essential to minimize the effects of atomic diffusion in the context of chemical tagging.},
  journal = {ApJ},
  keywords = {stars: abundances,stars: evolution}
}

@article{Dotter2016,
  title = {{{MESA Isochrones}} and {{Stellar Tracks}} ({{MIST}}) 0: {{Methods}} for the {{Construction}} of {{Stellar Isochrones}}},
  shorttitle = {{{MESA Isochrones}} and {{Stellar Tracks}} ({{MIST}}) 0},
  author = {Dotter, Aaron},
  year = {2016},
  month = jan,
  volume = {222},
  pages = {8},
  doi = {10.3847/0067-0049/222/1/8},
  abstract = {I describe a method to transform a set of stellar evolution tracks onto  a uniform basis and then interpolate within that basis to construct stellar isochrones. This method accommodates a broad range of stellar types, from substellar objects to high-mass stars, and phases of evolution, from the pre-main sequence to the white dwarf cooling sequence. I discuss situations in which stellar physics leads to departures from the otherwise monotonic relation between initial stellar mass and lifetime, and how these may be dealt with in isochrone construction. I close with convergence tests and recommendations for the number of points in the uniform basis and the mass between tracks in the original grid required to achieve a certain level accuracy in the resulting isochrones. The programs that implement these methods are free and open-source; they may be obtained from the project webpage.1},
  journal = {ApJS},
  keywords = {methods: numerical,stars: evolution}
}

@article{Dunkley.Komatsu.ea2009,
  title = {Five-{{Year Wilkinson Microwave Anisotropy Probe Observations}}: {{Likelihoods}} and {{Parameters}} from the {{WMAP Data}}},
  shorttitle = {Five-{{Year Wilkinson Microwave Anisotropy Probe Observations}}},
  author = {Dunkley, J. and Komatsu, E. and Nolta, M. R. and Spergel, D. N. and Larson, D. and Hinshaw, G. and Page, L. and Bennett, C. L. and Gold, B. and Jarosik, N. and Weiland, J. L. and Halpern, M. and Hill, R. S. and Kogut, A. and Limon, M. and Meyer, S. S. and Tucker, G. S. and Wollack, E. and Wright, E. L.},
  year = {2009},
  month = feb,
  volume = {180},
  pages = {306--329},
  doi = {10.1088/0067-0049/180/2/306},
  abstract = {This paper focuses on cosmological constraints derived from analysis of  WMAP data alone. A simple {$\Lambda$}CDM cosmological model fits the five-year WMAP temperature and polarization data. The basic parameters of the model are consistent with the three-year data and now better constrained: {$\Omega$} b h 2 = 0.02273 {$\pm$} 0.00062, {$\Omega$} c h 2 = 0.1099 {$\pm$} 0.0062, {$\Omega\Lambda$} = 0.742 {$\pm$} 0.030, ns = 0.963+0.014 -0.015, {$\tau$} = 0.087 {$\pm$} 0.017, and {$\sigma$}8 = 0.796 {$\pm$} 0.036, with h = 0.719+0.026 -0.027. With five years of polarization data, we have measured the optical depth to reionization, {$\tau>$}0, at 5{$\sigma$} significance. The redshift of an instantaneous reionization is constrained to be z reion = 11.0 {$\pm$} 1.4 with 68\% confidence. The 2{$\sigma$} lower limit is z reion {$>$} 8.2, and the 3{$\sigma$} limit is z reion {$>$} 6.7. This excludes a sudden reionization of the universe at z = 6 at more than 3.5{$\sigma$} significance, suggesting that reionization was an extended process. Using two methods for polarized foreground cleaning we get consistent estimates for the optical depth, indicating an error due to the foreground treatment of {$\tau$} \textasciitilde{} 0.01. This cosmological model also fits small-scale cosmic microwave background (CMB) data, and a range of astronomical data measuring the expansion rate and clustering of matter in the universe. We find evidence for the first time in the CMB power spectrum for a nonzero cosmic neutrino background, or a background of relativistic species, with the standard three light neutrino species preferred over the best-fit {$\Lambda$}CDM model with N eff = 0 at {$>$}99.5\% confidence, and N eff {$>$} 2.3(95\%confidence limit (CL)) when varied. The five-year WMAP data improve the upper limit on the tensor-to-scalar ratio, r {$<$} 0.43(95\%CL), for power-law models, and halve the limit on r for models with a running index, r {$<$} 0.58(95\%CL). With longer integration we find no evidence for a running spectral index, with dns /dln k = -0.037 {$\pm$} 0.028, and find improved limits on isocurvature fluctuations. The current WMAP-only limit on the sum of the neutrino masses is {$\sum$}m {$\nu$} {$<$} 1.3 eV(95\%CL), which is robust, to within 10\%, to a varying tensor amplitude, running spectral index, or dark energy equation of state. WMAP is the result of a partnership between Princeton University and NASA's Goddard Space Flight Center. Scientific guidance is provided by the WMAP Science Team.},
  journal = {ApJS},
  keywords = {cosmic microwave background,cosmology: observations,early universe,polarization}
}

@book{Eddington1926,
  title = {The {{Internal Constitution}} of the {{Stars}}},
  author = {Eddington, A. S.},
  year = {1926},
  publisher = {{Cambridge University Press}},
  address = {{Cambridge}},
  abstract = {Foreword; Preface; 1. Survey of the problem; 2. Thermodynamics of radiation;   3. Quantum theory; 4. Polytropic gas spheres; 5. Radiative equilibrium; 6. Solution of the equations; 7. The mass-luminosity relation; 8. Variable stars; 9. The coefficient of opacity; 10. Ionisation, diffusion, rotation; 11. The source of stellar energy; 12. The outside of a star; 13. Diffuse matter in space; Appendixes; Index.},
  isbn = {978-0-521-33708-3}
}

@article{Ferguson.Alexander.ea2005,
  title = {Low-{{Temperature Opacities}}},
  author = {Ferguson, Jason W. and Alexander, David R. and Allard, France and Barman, Travis and Bodnarik, Julia G. and Hauschildt, Peter H. and {Heffner-Wong}, Amanda and Tamanai, Akemi},
  year = {2005},
  month = apr,
  volume = {623},
  pages = {585--596},
  issn = {0004-637X},
  doi = {10.1086/428642},
  abstract = {Previous computations of low-temperature Rosseland and Planck mean opacities from Alexander \& Ferguson are updated and expanded. The new computations include a more complete equation of state (EOS) with more grain species and updated optical constants. Grains are now explicitly included in thermal equilibrium in the EOS calculation, which allows for a much wider range of grain compositions to be accurately included than was previously the case. The inclusion of high-temperature condensates such as Al2O3 and CaTiO3 significantly affects the total opacity over a narrow range of temperatures before the appearance of the first silicate grains. The new opacity tables are tabulated for temperatures ranging from 30,000 to 500 K with gas densities from 10-4 to 10-19 g cm-3. Comparisons with previous Rosseland mean opacity calculations are discussed. At high temperatures, the agreement with OPAL and Opacity Project is quite good. Comparisons at lower temperatures are more divergent as a result of differences in molecular and grain physics included in different calculations. The computation of Planck mean opacities performed with the opacity sampling method is shown to require a very large number of opacity sampling wavelength points; previously published results obtained with fewer wavelength points are shown to be significantly in error. Methods for requesting or obtaining the new tables are provided.},
  journal = {ApJ},
  keywords = {Atomic Data,Equation of State,Methods: Numerical,Molecular Data}
}

@article{Feuillet.Bovy.ea2016,
  title = {Determining {{Ages}} of {{APOGEE Giants}} with {{Known Distances}}},
  author = {Feuillet, Diane K. and Bovy, Jo and Holtzman, Jon and Girardi, L{\'e}o and MacDonald, Nick and Majewski, Steven R. and Nidever, David L.},
  year = {2016},
  month = jan,
  volume = {817},
  pages = {40},
  issn = {0004-637X},
  doi = {10.3847/0004-637X/817/1/40},
  abstract = {We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R {$\sim$} 22,500), near infrared (1.51-1.7 {$\mu$}m) APOGEE spectra provide measurements of stellar atmospheric parameters (temperature, surface gravity, [M/H], and [{$\alpha$}/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 30\%. For giants, the relatively rapid evolution up the red giant branch allows the age to be constrained by the mass. We examine methods of estimating age using both the mass-age relation directly and a Bayesian isochrone matching of measured parameters, assuming a constant SFH. To improve the SFH prior, we use a hierarchical modeling approach to constrain the parameters of the model SFH using the age probability distribution functions of the data. The results of an {$\alpha$}-dependent Gaussian SFH model show a clear age-[{$\alpha$}/M] relation at all ages. Using this SFH model as the prior for an empirical Bayesian analysis, we determine ages for individual stars. The resulting age-metallicity relation is flat, with a slight decrease in [M/H] at the oldest ages and a {$\sim$}0.5 dex spread in metallicity across most ages. For stars with ages {$\lessequivlnt$}1 Gyr we find a smaller spread, consistent with radial migration having a smaller effect on these young stars than on the older stars.},
  journal = {The Astrophysical Journal},
  keywords = {Galaxy: disk,Galaxy: evolution,stars: abundances,stars: fundamental parameters}
}

@article{Foreman-Mackey.Hogg.ea2013,
  title = {Emcee: {{The MCMC Hammer}}},
  shorttitle = {Emcee},
  author = {{Foreman-Mackey}, Daniel and Hogg, David W. and Lang, Dustin and Goodman, Jonathan},
  year = {2013},
  month = mar,
  volume = {125},
  pages = {306},
  issn = {0004-6280},
  doi = {10.1086/670067},
  abstract = {We introduce a stable, well tested Python implementation of the affine-invariant ensemble sampler for Markov chain Monte Carlo (MCMC) proposed by Goodman \& Weare (2010). The code is open source and has already been used in several published projects in the astrophysics literature. The algorithm behind emcee has several advantages over traditional MCMC sampling methods and it has excellent performance as measured by the autocorrelation time (or function calls per independent sample). One major advantage of the algorithm is that it requires hand-tuning of only 1 or 2 parameters compared to \texttildelow N2 for a traditional algorithm in an N-dimensional parameter space. In this document, we describe the algorithm and the details of our implementation. Exploiting the parallelism of the ensemble method, emcee permits any user to take advantage of multiple CPU cores without extra effort. The code is available online at http://dan.iel.fm/emcee under the GNU General Public License v2.},
  journal = {PASP},
  keywords = {python,statistical analysis}
}

@article{Frankel.Sanders.ea2020,
  title = {Keeping {{It Cool}}: {{Much Orbit Migration}}, yet {{Little Heating}}, in the {{Galactic Disk}}},
  shorttitle = {Keeping {{It Cool}}},
  author = {Frankel, Neige and Sanders, Jason and Ting, Yuan-Sen and Rix, Hans-Walter},
  year = {2020},
  month = jun,
  volume = {896},
  pages = {15},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/ab910c},
  abstract = {A star in the Milky Way's disk can now be at a Galactocentric radius quite distant from its birth radius for two reasons: either its orbit has become eccentric through radial heating, which increases its radial action JR ("blurring"), or merely its angular momentum Lz has changed and thereby its guiding radius ("churning"). We know that radial orbit migration is strong in the Galactic low-{$\alpha$} disk and set out to quantify the relative importance of these two effects, by devising and applying a parameterized model ( \$\{\{\textbackslash boldsymbol\{p\}\}\}\_\{\{\textbackslash boldsymbol\{m\}\}\}\$ ) for the distribution \$p(\{L\}\_\{z\},\{J\}\_\{R\},\textbackslash tau ,\textbackslash left[\textbackslash mathrm\{Fe\}/\{\textbackslash rm\{H\}\}\textbackslash right]| \{\{\textbackslash boldsymbol\{p\}\}\}\_\{\{\textbackslash boldsymbol\{m\}\}\})\$ in the stellar disk. This model describes the orbit evolution for stars of age {$\tau$} and metallicity \$\textbackslash left[\textbackslash mathrm\{Fe\}/\{\textbackslash rm\{H\}\}\textbackslash right]\$ , presuming that coeval stars were initially born on (near-)circular orbits, and with a unique \$\textbackslash left[\textbackslash mathrm\{Fe\}/\{\textbackslash rm\{H\}\}\textbackslash right]\$ at a given birth angular momentum and age. We fit this model to APOGEE red clump stars, accounting for the complex selection function of the survey. The best-fit model implies changes of angular momentum of \$\textbackslash sqrt\{\textbackslash langle \{\textbackslash rm\{\textbackslash Delta \}\}\{L\}\_\{z\}\{\textbackslash rangle \}\^\{2\}\}\textbackslash approx 619\textbackslash,\textbackslash mathrm\{kpc\}\textbackslash,\textbackslash mathrm\{km\}\textbackslash,\{\{\textbackslash rm\{s\}\}\}\^\{-1\}\textbackslash{} \{(\textbackslash tau /6\textbackslash mathrm\{Gyr\})\}\^\{0.5\}\$ and changes of radial action as \$\textbackslash sqrt\{\textbackslash langle \{\textbackslash rm\{\textbackslash Delta \}\}\{J\}\_\{R\}\{\textbackslash rangle \}\^\{2\}\}\textbackslash approx 63\textbackslash,\textbackslash mathrm\{kpc\}\textbackslash,\textbackslash mathrm\{km\}\textbackslash,\{\{\textbackslash rm\{s\}\}\}\^\{-1\}\{(\textbackslash tau /6\textbackslash mathrm\{Gyr\})\}\^\{0.6\}\$ at 8 kpc. This suggests that the secular orbit evolution of the disk is dominated by diffusion in angular momentum, with radial heating being an order of magnitude lower.},
  journal = {The Astrophysical Journal},
  keywords = {1050,1051,1052,1054,1594,574,591,Galaxy abundances,Galaxy dynamics,Galaxy stellar disks,Milky Way disk,Milky Way dynamics,Milky Way evolution,Milky Way Galaxy}
}

@article{Frebel2010,
  title = {Stellar Archaeology: {{Exploring}} the {{Universe}} with Metal-Poor Stars},
  shorttitle = {Stellar Archaeology},
  author = {Frebel, A.},
  year = {2010},
  month = may,
  volume = {331},
  pages = {474--488},
  doi = {10.1002/asna.201011362},
  abstract = {The abundance patterns of the most metal-poor stars in the Galactic halo and small dwarf galaxies provide us with a wealth of information about the early Universe. In particular, these old survivors allow us to study the nature of the first stars and supernovae, the relevant nucleosynthesis processes responsible for the formation and evolution of the elements, early star- and galaxy formation processes, as well as the assembly process of the stellar halo from dwarf galaxies a long time ago. This review presents the current state of the field of ``stellar archaeology'' - the diverse use of metal-poor stars to explore the high-redshift Universe and its constituents. In particular, the conditions for early star formation are discussed, how these ultimately led to a chemical evolution, and what the role of the most iron-poor stars is for learning about Population III supernovae yields. Rapid neutron-capture signatures found in metal-poor stars can be used to obtain stellar ages, but also to constrain this complex nucleosynthesis process with observational measurements. Moreover, chemical abundances of extremely metal-poor stars in different types of dwarf galaxies can be used to infer details on the formation scenario of the halo and the role of dwarf galaxies as Galactic building blocks. I conclude with an outlook as to where this field may be heading within the next decade. A table of {$\sim$} 1000 metal-poor stars and their abundances as collected from the literature is provided in electronic format.},
  journal = {Astron. Nachrichten},
  keywords = {early Universe,Galaxy: halo,Galaxy: stellar content,stars: abundances,stars: Population II}
}

@article{Frohlich.Lean2004,
  title = {Solar Radiative Output and Its Variability: Evidence and Mechanisms},
  shorttitle = {Solar Radiative Output and Its Variability},
  author = {Fr{\"o}hlich, Claus and Lean, Judith},
  year = {2004},
  month = dec,
  volume = {12},
  pages = {273--320},
  issn = {0935-4956},
  doi = {10.1007/s00159-004-0024-1},
  abstract = {Electromagnetic radiation from the Sun is Earth's primary energy source. Space-based radiometric measurements in the past two decades have begun to establish the nature, magnitude and origins of its variability. An 11-year cycle with peak-to-peak amplitude of order 0.1 \% is now well established in recent total solar irradiance observations, as are larger variations of order 0.2 \% associated with the Sun's 27-day rotation period. The ultraviolet, visible and infrared spectral regions all participate in these variations, with larger changes at shorter wavelengths. Linkages of solar radiative output variations with solar magnetism are clearly identified. Active regions alter the local radiance, and their wavelength-dependent contrasts relative to the quiet Sun control the relative spectrum of irradiance variability. Solar radiative output also responds to sub-surface convection and to eruptive events on the Sun. On the shortest time scales, total irradiance exhibits five minute fluctuations of amplitude {$\approx$} 0.003 \%, and can increase to as much as 0.015 \% during the very largest solar flares. Unknown is whether multi-decadal changes in solar activity produce longer-term irradiance variations larger than observed thus far in the contemporary epoch. Empirical associations with solar activity proxies suggest reduced total solar irradiance during the anomalously low activity in the seventeenth century Maunder Minimum relative to the present. Uncertainties in understanding the physical relationships between direct magnetic modulation of solar radiative output and heliospheric modulation of cosmogenic proxies preclude definitive historical irradiance estimates, as yet.},
  journal = {A\&ARv},
  keywords = {activity,solar-terrestrial relations,Sun: irradiance,UV radiation}
}

@article{GaiaCollaboration.Brown.ea2018,
  title = {Gaia {{Data Release}} 2. {{Summary}} of the Contents and Survey Properties},
  author = {{Gaia Collaboration} and Brown, A. G. A. and Vallenari, A. and Prusti, T. and {de Bruijne}, J. H. J. and Babusiaux, C. and {Bailer-Jones}, C. A. L. and Biermann, M. and Evans, D. W. and Eyer, L. and Jansen, F. and Jordi, C. and Klioner, S. A. and Lammers, U. and Lindegren, L. and Luri, X. and Mignard, F. and Panem, C. and Pourbaix, D. and Randich, S. and Sartoretti, P. and Siddiqui, H. I. and Soubiran, C. and {van Leeuwen}, F. and Walton, N. A. and Arenou, F. and Bastian, U. and Cropper, M. and Drimmel, R. and Katz, D. and Lattanzi, M. G. and Bakker, J. and Cacciari, C. and Casta{\~n}eda, J. and Chaoul, L. and Cheek, N. and De Angeli, F. and Fabricius, C. and Guerra, R. and Holl, B. and Masana, E. and Messineo, R. and Mowlavi, N. and Nienartowicz, K. and Panuzzo, P. and Portell, J. and Riello, M. and Seabroke, G. M. and Tanga, P. and Th{\'e}venin, F. and {Gracia-Abril}, G. and Comoretto, G. and {Garcia-Reinaldos}, M. and Teyssier, D. and Altmann, M. and Andrae, R. and Audard, M. and {Bellas-Velidis}, I. and Benson, K. and Berthier, J. and Blomme, R. and Burgess, P. and Busso, G. and Carry, B. and Cellino, A. and Clementini, G. and Clotet, M. and Creevey, O. and Davidson, M. and De Ridder, J. and Delchambre, L. and Dell'Oro, A. and Ducourant, C. and {Fern{\'a}ndez-Hern{\'a}ndez}, J. and Fouesneau, M. and Fr{\'e}mat, Y. and Galluccio, L. and {Garc{\'i}a-Torres}, M. and {Gonz{\'a}lez-N{\'u}{\~n}ez}, J. and {Gonz{\'a}lez-Vidal}, J. J. and Gosset, E. and Guy, L. P. and Halbwachs, J.-L. and Hambly, N. C. and Harrison, D. L. and Hern{\'a}ndez, J. and Hestroffer, D. and Hodgkin, S. T. and Hutton, A. and Jasniewicz, G. and {Jean-Antoine-Piccolo}, A. and Jordan, S. and Korn, A. J. and {Krone-Martins}, A. and Lanzafame, A. C. and Lebzelter, T. and L{\"o}ffler, W. and Manteiga, M. and Marrese, P. M. and {Mart{\'i}n-Fleitas}, J. M. and Moitinho, A. and Mora, A. and Muinonen, K. and Osinde, J. and Pancino, E. and Pauwels, T. and Petit, J.-M. and {Recio-Blanco}, A. and Richards, P. J. and Rimoldini, L. and Robin, A. C. and Sarro, L. M. and Siopis, C. and Smith, M. and Sozzetti, A. and S{\"u}veges, M. and Torra, J. and {van Reeven}, W. and Abbas, U. and Abreu Aramburu, A. and Accart, S. and Aerts, C. and Altavilla, G. and {\'A}lvarez, M. A. and Alvarez, R. and Alves, J. and Anderson, R. I. and Andrei, A. H. and Anglada Varela, E. and Antiche, E. and Antoja, T. and Arcay, B. and Astraatmadja, T. L. and Bach, N. and Baker, S. G. and {Balaguer-N{\'u}{\~n}ez}, L. and Balm, P. and Barache, C. and Barata, C. and Barbato, D. and Barblan, F. and Barklem, P. S. and Barrado, D. and Barros, M. and Barstow, M. A. and Bartholom{\'e} Mu{\~n}oz, S. and Bassilana, J.-L. and Becciani, U. and Bellazzini, M. and Berihuete, A. and Bertone, S. and Bianchi, L. and Bienaym{\'e}, O. and {Blanco-Cuaresma}, S. and Boch, T. and Boeche, C. and Bombrun, A. and Borrachero, R. and Bossini, D. and Bouquillon, S. and Bourda, G. and Bragaglia, A. and Bramante, L. and Breddels, M. A. and Bressan, A. and Brouillet, N. and Br{\"u}semeister, T. and Brugaletta, E. and Bucciarelli, B. and Burlacu, A. and Busonero, D. and Butkevich, A. G. and Buzzi, R. and Caffau, E. and Cancelliere, R. and Cannizzaro, G. and {Cantat-Gaudin}, T. and Carballo, R. and Carlucci, T. and Carrasco, J. M. and Casamiquela, L. and Castellani, M. and {Castro-Ginard}, A. and Charlot, P. and Chemin, L. and Chiavassa, A. and Cocozza, G. and Costigan, G. and Cowell, S. and Crifo, F. and Crosta, M. and Crowley, C. and Cuypers, J. and Dafonte, C. and Damerdji, Y. and Dapergolas, A. and David, P. and David, M. and {de Laverny}, P. and De Luise, F. and De March, R. and {de Martino}, D. and {de Souza}, R. and {de Torres}, A. and Debosscher, J. and {del Pozo}, E. and Delbo, M. and Delgado, A. and Delgado, H. E. and Di Matteo, P. and Diakite, S. and Diener, C. and Distefano, E. and Dolding, C. and Drazinos, P. and Dur{\'a}n, J. and Edvardsson, B. and Enke, H. and Eriksson, K. and Esquej, P. and Eynard Bontemps, G. and Fabre, C. and Fabrizio, M. and Faigler, S. and Falc{\~a}o, A. J. and Farr{\`a}s Casas, M. and Federici, L. and Fedorets, G. and Fernique, P. and Figueras, F. and Filippi, F. and Findeisen, K. and Fonti, A. and Fraile, E. and Fraser, M. and Fr{\'e}zouls, B. and Gai, M. and Galleti, S. and Garabato, D. and {Garc{\'i}a-Sedano}, F. and Garofalo, A. and Garralda, N. and Gavel, A. and Gavras, P. and Gerssen, J. and Geyer, R. and Giacobbe, P. and Gilmore, G. and Girona, S. and Giuffrida, G. and Glass, F. and Gomes, M. and Granvik, M. and Gueguen, A. and Guerrier, A. and Guiraud, J. and {Guti{\'e}rrez-S{\'a}nchez}, R. and Haigron, R. and Hatzidimitriou, D. and Hauser, M. and Haywood, M. and Heiter, U. and Helmi, A. and Heu, J. and Hilger, T. and Hobbs, D. and Hofmann, W. and Holland, G. and Huckle, H. E. and Hypki, A. and Icardi, V. and Jan{\ss}en, K. and {Jevardat de Fombelle}, G. and Jonker, P. G. and Juh{\'a}sz, {\'A}. L. and Julbe, F. and Karampelas, A. and Kewley, A. and Klar, J. and Kochoska, A. and Kohley, R. and Kolenberg, K. and Kontizas, M. and Kontizas, E. and Koposov, S. E. and Kordopatis, G. and {Kostrzewa-Rutkowska}, Z. and Koubsky, P. and Lambert, S. and Lanza, A. F. and Lasne, Y. and Lavigne, J.-B. and Le Fustec, Y. and {Le Poncin-Lafitte}, C. and Lebreton, Y. and Leccia, S. and Leclerc, N. and {Lecoeur-Taibi}, I. and Lenhardt, H. and Leroux, F. and Liao, S. and Licata, E. and Lindstr{\o}m, H. E. P. and Lister, T. A. and Livanou, E. and Lobel, A. and L{\'o}pez, M. and Managau, S. and Mann, R. G. and Mantelet, G. and Marchal, O. and Marchant, J. M. and Marconi, M. and Marinoni, S. and Marschalk{\'o}, G. and Marshall, D. J. and Martino, M. and Marton, G. and Mary, N. and Massari, D. and Matijevi{\v c}, G. and Mazeh, T. and McMillan, P. J. and Messina, S. and Michalik, D. and Millar, N. R. and Molina, D. and Molinaro, R. and Moln{\'a}r, L. and Montegriffo, P. and Mor, R. and Morbidelli, R. and Morel, T. and Morris, D. and Mulone, A. F. and Muraveva, T. and Musella, I. and Nelemans, G. and Nicastro, L. and Noval, L. and O'Mullane, W. and Ord{\'e}novic, C. and {Ord{\'o}{\~n}ez-Blanco}, D. and Osborne, P. and Pagani, C. and Pagano, I. and Pailler, F. and Palacin, H. and Palaversa, L. and Panahi, A. and Pawlak, M. and Piersimoni, A. M. and Pineau, F.-X. and Plachy, E. and Plum, G. and Poggio, E. and Poujoulet, E. and Pr{\v s}a, A. and Pulone, L. and Racero, E. and Ragaini, S. and Rambaux, N. and {Ramos-Lerate}, M. and Regibo, S. and Reyl{\'e}, C. and Riclet, F. and Ripepi, V. and Riva, A. and Rivard, A. and Rixon, G. and Roegiers, T. and Roelens, M. and {Romero-G{\'o}mez}, M. and Rowell, N. and Royer, F. and {Ruiz-Dern}, L. and Sadowski, G. and Sagrist{\`a} Sell{\'e}s, T. and Sahlmann, J. and Salgado, J. and Salguero, E. and Sanna, N. and {Santana-Ros}, T. and Sarasso, M. and Savietto, H. and Schultheis, M. and Sciacca, E. and Segol, M. and Segovia, J. C. and S{\'e}gransan, D. and Shih, I.-C. and Siltala, L. and Silva, A. F. and Smart, R. L. and Smith, K. W. and Solano, E. and Solitro, F. and Sordo, R. and Soria Nieto, S. and Souchay, J. and Spagna, A. and Spoto, F. and Stampa, U. and Steele, I. A. and Steidelm{\"u}ller, H. and Stephenson, C. A. and Stoev, H. and Suess, F. F. and Surdej, J. and Szabados, L. and {Szegedi-Elek}, E. and Tapiador, D. and Taris, F. and Tauran, G. and Taylor, M. B. and Teixeira, R. and Terrett, D. and Teyssandier, P. and Thuillot, W. and Titarenko, A. and Torra Clotet, F. and Turon, C. and Ulla, A. and Utrilla, E. and Uzzi, S. and Vaillant, M. and Valentini, G. and Valette, V. and {van Elteren}, A. and Van Hemelryck, E. and {van Leeuwen}, M. and Vaschetto, M. and Vecchiato, A. and Veljanoski, J. and Viala, Y. and Vicente, D. and Vogt, S. and {von Essen}, C. and Voss, H. and Votruba, V. and Voutsinas, S. and Walmsley, G. and Weiler, M. and Wertz, O. and Wevers, T. and Wyrzykowski, {\L}. and Yoldas, A. and {\v Z}erjal, M. and Ziaeepour, H. and Zorec, J. and Zschocke, S. and Zucker, S. and Zurbach, C. and Zwitter, T.},
  year = {2018},
  month = aug,
  volume = {616},
  pages = {A1},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201833051},
  abstract = {Context. We present the second Gaia data release, Gaia DR2, consisting of astrometry, photometry, radial velocities, and information on astrophysical parameters and variability, for sources brighter than magnitude 21. In addition epoch astrometry and photometry are provided for a modest sample of minor planets in the solar system. Aims: A summary of the contents of Gaia DR2 is presented, accompanied by a discussion on the differences with respect to Gaia DR1 and an overview of the main limitations which are still present in the survey. Recommendations are made on the responsible use of Gaia DR2 results. Methods: The raw data collected with the Gaia instruments during the first 22 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into this second data release, which represents a major advance with respect to Gaia DR1 in terms of completeness, performance, and richness of the data products. Results: Gaia DR2 contains celestial positions and the apparent brightness in G for approximately 1.7 billion sources. For 1.3 billion of those sources, parallaxes and proper motions are in addition available. The sample of sources for which variability information is provided is expanded to 0.5 million stars. This data release contains four new elements: broad-band colour information in the form of the apparent brightness in the GBP (330-680 nm) and GRP (630-1050 nm) bands is available for 1.4 billion sources; median radial velocities for some 7 million sources are presented; for between 77 and 161 million sources estimates are provided of the stellar effective temperature, extinction, reddening, and radius and luminosity; and for a pre-selected list of 14 000 minor planets in the solar system epoch astrometry and photometry are presented. Finally, Gaia DR2 also represents a new materialisation of the celestial reference frame in the optical, the Gaia-CRF2, which is the first optical reference frame based solely on extragalactic sources. There are notable changes in the photometric system and the catalogue source list with respect to Gaia DR1, and we stress the need to consider the two data releases as independent. Conclusions: Gaia DR2 represents a major achievement for the Gaia mission, delivering on the long standing promise to provide parallaxes and proper motions for over 1 billion stars, and representing a first step in the availability of complementary radial velocity and source astrophysical information for a sample of stars in the Gaia survey which covers a very substantial fraction of the volume of our galaxy.},
  journal = {A\&A},
  keywords = {asteroids: general,astrometry,catalogs,Gaia,minor planets,missions,stars: fundamental parameters,stars: variables: general,techniques: radial velocities}
}

@article{GaiaCollaboration.Prusti.ea2016,
  title = {The {{Gaia}} Mission},
  author = {{Gaia Collaboration} and Prusti, T. and {de Bruijne}, J. H. J. and Brown, A. G. A. and Vallenari, A. and Babusiaux, C. and {Bailer-Jones}, C. A. L. and Bastian, U. and Biermann, M. and Evans, D. W. and Eyer, L. and Jansen, F. and Jordi, C. and Klioner, S. A. and Lammers, U. and Lindegren, L. and Luri, X. and Mignard, F. and Milligan, D. J. and Panem, C. and Poinsignon, V. and Pourbaix, D. and Randich, S. and Sarri, G. and Sartoretti, P. and Siddiqui, H. I. and Soubiran, C. and Valette, V. and {van Leeuwen}, F. and Walton, N. A. and Aerts, C. and Arenou, F. and Cropper, M. and Drimmel, R. and H{\o}g, E. and Katz, D. and Lattanzi, M. G. and O'Mullane, W. and Grebel, E. K. and Holland, A. D. and Huc, C. and Passot, X. and Bramante, L. and Cacciari, C. and Casta{\~n}eda, J. and Chaoul, L. and Cheek, N. and De Angeli, F. and Fabricius, C. and Guerra, R. and Hern{\'a}ndez, J. and {Jean-Antoine-Piccolo}, A. and Masana, E. and Messineo, R. and Mowlavi, N. and Nienartowicz, K. and {Ord{\'o}{\~n}ez-Blanco}, D. and Panuzzo, P. and Portell, J. and Richards, P. J. and Riello, M. and Seabroke, G. M. and Tanga, P. and Th{\'e}venin, F. and Torra, J. and Els, S. G. and {Gracia-Abril}, G. and Comoretto, G. and {Garcia-Reinaldos}, M. and Lock, T. and Mercier, E. and Altmann, M. and Andrae, R. and Astraatmadja, T. L. and {Bellas-Velidis}, I. and Benson, K. and Berthier, J. and Blomme, R. and Busso, G. and Carry, B. and Cellino, A. and Clementini, G. and Cowell, S. and Creevey, O. and Cuypers, J. and Davidson, M. and De Ridder, J. and {de Torres}, A. and Delchambre, L. and Dell'Oro, A. and Ducourant, C. and Fr{\'e}mat, Y. and {Garc{\'i}a-Torres}, M. and Gosset, E. and Halbwachs, J.-L. and Hambly, N. C. and Harrison, D. L. and Hauser, M. and Hestroffer, D. and Hodgkin, S. T. and Huckle, H. E. and Hutton, A. and Jasniewicz, G. and Jordan, S. and Kontizas, M. and Korn, A. J. and Lanzafame, A. C. and Manteiga, M. and Moitinho, A. and Muinonen, K. and Osinde, J. and Pancino, E. and Pauwels, T. and Petit, J.-M. and {Recio-Blanco}, A. and Robin, A. C. and Sarro, L. M. and Siopis, C. and Smith, M. and Smith, K. W. and Sozzetti, A. and Thuillot, W. and {van Reeven}, W. and Viala, Y. and Abbas, U. and Abreu Aramburu, A. and Accart, S. and Aguado, J. J. and Allan, P. M. and Allasia, W. and Altavilla, G. and {\'A}lvarez, M. A. and Alves, J. and Anderson, R. I. and Andrei, A. H. and Anglada Varela, E. and Antiche, E. and Antoja, T. and Ant{\'o}n, S. and Arcay, B. and Atzei, A. and Ayache, L. and Bach, N. and Baker, S. G. and {Balaguer-N{\'u}{\~n}ez}, L. and Barache, C. and Barata, C. and Barbier, A. and Barblan, F. and Baroni, M. and {Barrado y Navascu{\'e}s}, D. and Barros, M. and Barstow, M. A. and Becciani, U. and Bellazzini, M. and Bellei, G. and Bello Garc{\'i}a, A. and Belokurov, V. and Bendjoya, P. and Berihuete, A. and Bianchi, L. and Bienaym{\'e}, O. and Billebaud, F. and Blagorodnova, N. and {Blanco-Cuaresma}, S. and Boch, T. and Bombrun, A. and Borrachero, R. and Bouquillon, S. and Bourda, G. and Bouy, H. and Bragaglia, A. and Breddels, M. 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J. and Granvik, M. and Guerrier, A. and Guillout, P. and Guiraud, J. and G{\'u}rpide, A. and {Guti{\'e}rrez-S{\'a}nchez}, R. and Guy, L. P. and Haigron, R. and Hatzidimitriou, D. and Haywood, M. and Heiter, U. and Helmi, A. and Hobbs, D. and Hofmann, W. and Holl, B. and Holland, G. and Hunt, J. A. S. and Hypki, A. and Icardi, V. and Irwin, M. and {Jevardat de Fombelle}, G. and Jofr{\'e}, P. and Jonker, P. G. and Jorissen, A. and Julbe, F. and Karampelas, A. and Kochoska, A. and Kohley, R. and Kolenberg, K. and Kontizas, E. and Koposov, S. E. and Kordopatis, G. and Koubsky, P. and Kowalczyk, A. and {Krone-Martins}, A. and Kudryashova, M. and Kull, I. and Bachchan, R. K. and {Lacoste-Seris}, F. and Lanza, A. F. and Lavigne, J.-B. and {Le Poncin-Lafitte}, C. and Lebreton, Y. and Lebzelter, T. and Leccia, S. and Leclerc, N. and {Lecoeur-Taibi}, I. and Lemaitre, V. and Lenhardt, H. and Leroux, F. and Liao, S. and Licata, E. and Lindstr{\o}m, H. E. P. and Lister, T. A. and Livanou, E. and Lobel, A. and L{\"o}ffler, W. and L{\'o}pez, M. and {Lopez-Lozano}, A. and Lorenz, D. and Loureiro, T. and MacDonald, I. and Magalh{\~a}es Fernandes, T. and Managau, S. and Mann, R. G. and Mantelet, G. and Marchal, O. and Marchant, J. M. and Marconi, M. and Marie, J. and Marinoni, S. and Marrese, P. M. and Marschalk{\'o}, G. and Marshall, D. J. and {Mart{\'i}n-Fleitas}, J. M. and Martino, M. and Mary, N. and Matijevi{\v c}, G. and Mazeh, T. and McMillan, P. J. and Messina, S. and Mestre, A. and Michalik, D. and Millar, N. R. and Miranda, B. M. H. and Molina, D. and Molinaro, R. and Molinaro, M. and Moln{\'a}r, L. and Moniez, M. and Montegriffo, P. and Monteiro, D. and Mor, R. and Mora, A. and Morbidelli, R. and Morel, T. and Morgenthaler, S. and Morley, T. and Morris, D. and Mulone, A. F. and Muraveva, T. and Musella, I. and Narbonne, J. and Nelemans, G. and Nicastro, L. and Noval, L. and Ord{\'e}novic, C. and {Ordieres-Mer{\'e}}, J. and Osborne, P. and Pagani, C. and Pagano, I. and Pailler, F. and Palacin, H. and Palaversa, L. and Parsons, P. and Paulsen, T. and Pecoraro, M. and Pedrosa, R. and Pentik{\"a}inen, H. and Pereira, J. and Pichon, B. and Piersimoni, A. M. and Pineau, F.-X. and Plachy, E. and Plum, G. and Poujoulet, E. and Pr{\v s}a, A. and Pulone, L. and Ragaini, S. and Rago, S. and Rambaux, N. and {Ramos-Lerate}, M. and Ranalli, P. and Rauw, G. and Read, A. and Regibo, S. and Renk, F. and Reyl{\'e}, C. and Ribeiro, R. A. and Rimoldini, L. and Ripepi, V. and Riva, A. and Rixon, G. and Roelens, M. and {Romero-G{\'o}mez}, M. and Rowell, N. and Royer, F. and Rudolph, A. and {Ruiz-Dern}, L. and Sadowski, G. and Sagrist{\`a} Sell{\'e}s, T. and Sahlmann, J. and Salgado, J. and Salguero, E. and Sarasso, M. and Savietto, H. and Schnorhk, A. and Schultheis, M. and Sciacca, E. and Segol, M. and Segovia, J. C. and Segransan, D. and Serpell, E. and Shih, I.-C. and Smareglia, R. and Smart, R. L. and Smith, C. and Solano, E. and Solitro, F. and Sordo, R. and Soria Nieto, S. and Souchay, J. and Spagna, A. and Spoto, F. and Stampa, U. and Steele, I. A. and Steidelm{\"u}ller, H. and Stephenson, C. A. and Stoev, H. and Suess, F. F. and S{\"u}veges, M. and Surdej, J. and Szabados, L. and {Szegedi-Elek}, E. and Tapiador, D. and Taris, F. and Tauran, G. and Taylor, M. B. and Teixeira, R. and Terrett, D. and Tingley, B. and Trager, S. 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  year = {2016},
  month = nov,
  volume = {595},
  pages = {A1},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201629272},
  abstract = {Gaia is a cornerstone mission in the science programme of the EuropeanSpace Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page. http://www.cosmos.esa.int/gaia},
  journal = {A\&A},
  keywords = {astrometry,Gaia,Galaxy: structure,missions,parallaxes,proper motions,space vehicles: instruments,telescopes}
}

@article{Garcia.Ballot2019,
  title = {Asteroseismology of Solar-Type Stars},
  author = {Garc{\'i}a, Rafael A. and Ballot, J{\'e}r{\^o}me},
  year = {2019},
  month = sep,
  volume = {16},
  pages = {4},
  doi = {10.1007/s41116-019-0020-1},
  abstract = {Until the last few decades, investigations of stellar interiors had been restricted to theoretical studies only constrained by observations of their global properties and external characteristics. However, in the last 30 years the field has been revolutionized by the ability to perform seismic investigations of stellar interiors. This revolution begun with the Sun, where helioseismology has been yielding information competing with what can be inferred about the Earth's interior from geoseismology. The last two decades have witnessed the advent of asteroseismology of solar-like stars, thanks to a dramatic development of new observing facilities providing the first reliable results on the interiors of distant stars. The coming years will see a huge development in this field. In this review we focus on solar-type stars, i.e., cool main-sequence stars where oscillations are stochastically excited by surface convection. After a short introduction and a historical overview of the discipline, we review the observational techniques generally used, and we describe the theory behind stellar oscillations in cool main-sequence stars. We continue with a complete description of the normal mode analyses through which it is possible to extract the physical information about the structure and dynamics of the stars. We then summarize the lessons that we have learned and discuss unsolved issues and questions that are still unanswered.},
  journal = {Living Rev. Sol. Phys.},
  keywords = {Asteroseismology,Solar analogs,Stellar oscillations}
}

@article{Garcia.Mathur.ea2010,
  title = {{{CoRoT Reveals}} a {{Magnetic Activity Cycle}} in a {{Sun}}-{{Like Star}}},
  author = {Garc{\'i}a, Rafael A. and Mathur, Savita and Salabert, David and Ballot, J{\'e}r{\^o}me and R{\'e}gulo, Clara and Metcalfe, Travis S. and Baglin, Annie},
  year = {2010},
  month = aug,
  volume = {329},
  pages = {1032},
  issn = {0036-8075},
  doi = {10.1126/science.1191064},
  abstract = {The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT space mission, showing solarlike oscillations in the star HD49933, for signatures of stellar magnetic activity. Asteroseismic measurements of global changes in the oscillation frequencies and mode amplitudes reveal a modulation of at least 120 days, with the minimum frequency shift corresponding to maximum amplitude as in the Sun. These observations are evidence of a stellar magnetic activity cycle taking place beneath the surface of HD49933 and provide constraints for stellar dynamo models under conditions different from those of the Sun.},
  journal = {Science}
}

@article{GarciaPerez.AllendePrieto.ea2016,
  title = {{{ASPCAP}}: {{The APOGEE Stellar Parameter}} and {{Chemical Abundances Pipeline}}},
  shorttitle = {{{ASPCAP}}},
  author = {Garc{\'i}a P{\'e}rez, Ana E. and Allende Prieto, Carlos and Holtzman, Jon A. and Shetrone, Matthew and M{\'e}sz{\'a}ros, Szabolcs and Bizyaev, Dmitry and Carrera, Ricardo and Cunha, Katia and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Johnson, Jennifer A. and Majewski, Steven R. and Nidever, David L. and Schiavon, Ricardo P. and Shane, Neville and Smith, Verne V. and Sobeck, Jennifer and Troup, Nicholas and Zamora, Olga and Weinberg, David H. and Bovy, Jo and Eisenstein, Daniel J. and Feuillet, Diane and Frinchaboy, Peter M. and Hayden, Michael R. and Hearty, Fred R. and Nguyen, Duy C. and O'Connell, Robert W. and Pinsonneault, Marc H. and Wilson, John C. and Zasowski, Gail},
  year = {2016},
  month = jun,
  volume = {151},
  pages = {144},
  doi = {10.3847/0004-6256/151/6/144},
  abstract = {The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R {$\approx$} 22,500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using {$\chi$}2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2\%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.},
  journal = {AJ},
  keywords = {Galaxy: center,Galaxy: structure,methods: data analysis,stars: abundances,stars: atmospheres}
}

@article{Gelman.Rubin1992,
  title = {Inference from {{Iterative Simulation Using Multiple Sequences}}},
  author = {Gelman, Andrew and Rubin, Donald B.},
  year = {1992},
  volume = {7},
  pages = {457--472},
  doi = {10.1214/ss/1177011136},
  abstract = {The Gibbs sampler, the algorithm of Metropolis and similar iterative simulation methods are potentially very helpful for summarizing multivariate distributions. Used naively, however, iterative simulation can give misleading answers. Our methods are simple and generally applicable to the output of any iterative simulation; they are designed for researchers primarily interested in the science underlying the data and models they are analyzing, rather than for researchers interested in the probability theory underlying the iterative simulations themselves. Our recommended strategy is to use several independent sequences, with starting points sampled from an overdispersed distribution. At each step of the iterative simulation, we obtain, for each univariate estimand of interest, a distributional estimate and an estimate of how much sharper the distributional estimate might become if the simulations were continued indefinitely. Because our focus is on applied inference for Bayesian posterior distributions in real problems, which often tend toward normality after transformations and marginalization, we derive our results as normal-theory approximations to exact Bayesian inference, conditional on the observed simulations. The methods are illustrated on a random-effects mixture model applied to experimental measurements of reaction times of normal and schizophrenic patients.},
  journal = {Stat. Sci.}
}

@article{Ginsburg.Sipocz.ea2019,
  title = {Astroquery: {{An Astronomical Web}}-Querying {{Package}} in {{Python}}},
  shorttitle = {Astroquery},
  author = {Ginsburg, Adam and Sip{\H o}cz, Brigitta M. and Brasseur, C. E. and Cowperthwaite, Philip S. and Craig, Matthew W. and Deil, Christoph and Guillochon, James and Guzman, Giannina and Liedtke, Simon and Lian Lim, Pey and Lockhart, Kelly E. and Mommert, Michael and Morris, Brett M. and Norman, Henrik and Parikh, Madhura and Persson, Magnus V. and Robitaille, Thomas P. and Segovia, Juan-Carlos and Singer, Leo P. and Tollerud, Erik J. and {de Val-Borro}, Miguel and Valtchanov, Ivan and Woillez, Julien and {Astroquery Collaboration} and {a subset of astropy Collaboration}},
  year = {2019},
  month = mar,
  volume = {157},
  pages = {98},
  issn = {0004-6256},
  doi = {10.3847/1538-3881/aafc33},
  abstract = {astroquery is a collection of tools for requesting data from databases hosted on remote servers with interfaces exposed on the internet, including those with web pages but without formal application program interfaces. These tools are built on the Python requests package, which is used to make HTTP requests, and astropy, which provides most of the data parsing functionality. astroquery modules generally attempt to replicate the web page interface provided by a given service as closely as possible, making the transition from browser-based to command-line interaction easy. astroquery has received significant contributions from throughout the astronomical community, including several from telescope archives. astroquery enables the creation of fully reproducible workflows from data acquisition through publication. This paper describes the philosophy, basic structure, and development model of the astroquery package. The complete documentation for astroquery can be found at http://astroquery.readthedocs.io/.},
  journal = {AJ},
  keywords = {astronomical databases: miscellaneous,astronomy,python,virtual observatory tools}
}

@article{Glorot.Bordes.ea2011,
  title = {Deep Sparse Rectifier Neural Networks},
  author = {Glorot, Xavier and Bordes, Antoine and Bengio, Y.},
  year = {2011},
  month = jan,
  volume = {15},
  pages = {315--323},
  journal = {Proc. 14th Int. Conf. Artif. Intell. Statisitics AISTATS 2011}
}

@book{Goodfellow.Bengio.ea2016,
  title = {Deep Learning},
  author = {Goodfellow, Ian and Bengio, Yoshua and Courville, Aaron},
  year = {2016},
  publisher = {{MIT Press}},
  address = {{Cambridge}, {MA}}
}

@article{Gough1977,
  title = {Mixing-Length Theory for Pulsating Stars},
  author = {Gough, D. O.},
  year = {1977},
  month = may,
  volume = {214},
  pages = {196--213},
  doi = {10.1086/155244},
  abstract = {The mixing length theory of convection is generalized for use in the envelopes of nonrotating, radially pulsating stars by the methods proposed by Gough (1965) and Unno (1967). The essential differences between the physical assumptions made in the two approaches are explained. The detailed formulas required for a linear pulsational-stability analysis of a static star are derived.},
  journal = {ApJ},
  keywords = {Boussinesq Approximation,Convective Heat Transfer,Equations Of Motion,Fluctuation Theory,Mixing Length Flow Theory,Stellar Envelopes}
}

@article{Goupil2019,
  title = {Seismic Probe of Transport Processes in Red Giants},
  author = {Goupil, MarieJo},
  year = {2019},
  month = dec,
  volume = {88},
  pages = {115--146},
  abstract = {Seismic data obtained with the space photometric CoRoT and Kepler instruments have led to a unprecendently precise characterization- in terms of masses and ages- of a large sample of post main sequence stars (low mass subgiant and red giants). The high quality of the collected seismic data and the subsequent theoretical work for interpreting them brought up a series of issues which revealed that our knowledge of the internal properties of red giant stars remains quite limited. Two such important issues are discussed here, namely mixing beyond the convective core of helium burning red giant stars and evolution of internal angular momentum for post main sequence stars. This includes how they were diagnosed and what are the resulting improvements in our understanding regarding these issues (or rather how far we are from a proper understanding and realistic modelling of the structure and evolution of post main sequence stars).},
  journal = {Bulletin de la Societe Royale des Sciences de Liege},
  keywords = {asteroseismology,evolution,interiors,oscillations,red giants,stars}
}

@article{Green.Schlafly.ea2018,
  title = {Galactic Reddening in {{3D}} from Stellar Photometry - an Improved Map},
  author = {Green, Gregory M. and Schlafly, Edward F. and Finkbeiner, Douglas and Rix, Hans-Walter and Martin, Nicolas and Burgett, William and Draper, Peter W. and Flewelling, Heather and Hodapp, Klaus and Kaiser, Nicholas and Kudritzki, Rolf-Peter and Magnier, Eugene A. and Metcalfe, Nigel and Tonry, John L. and Wainscoat, Richard and Waters, Christopher},
  year = {2018},
  month = jul,
  volume = {478},
  pages = {651--666},
  doi = {10.1093/mnras/sty1008},
  abstract = {We present a new 3D map of interstellar dust reddening, covering three quarters of the sky (declinations of {$\delta$} {$\greaterequivlnt$} -30\textdegree ) out to a distance of several kiloparsecs. The map is based on high-quality stellar photometry of 800 million stars from Pan-STARRS 1 and 2MASS. We divide the sky into sightlines containing a few hundred stars each, and then infer stellar distances and types, along with the line-of-sight dust distribution. Our new map incorporates a more accurate average extinction law and an additional 1.5 yr of Pan-STARRS 1 data, tracing dust to greater extinctions and at higher angular resolutions than our previous map. Out of the plane of the Galaxy, our map agrees well with 2D reddening maps derived from far-infrared dust emission. After accounting for a 25 per cent difference in scale, we find a mean scatter of {$\sim$}10 per cent between our map and the Planck far-infrared emission-based dust map, out to a depth of 0.8 mag in E(gP1 - rP1), with the level of agreement varying over the sky. Our map can be downloaded at http://argonaut.skymaps.info, or from the Harvard Dataverse (Green 2017).},
  journal = {MNRAS},
  keywords = {dust,extinction,Galaxy: structure,ISM: structure}
}

@article{Green.Schlafly.ea2019,
  ids = {Green.Schlafly.ea2019a},
  title = {A {{3D Dust Map Based}} on {{Gaia}}, {{Pan}}-{{STARRS}} 1, and {{2MASS}}},
  author = {Green, Gregory M. and Schlafly, Edward and Zucker, Catherine and Speagle, Joshua S. and Finkbeiner, Douglas},
  year = {2019},
  month = dec,
  volume = {887},
  pages = {93},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/ab5362},
  abstract = {We present a new three-dimensional map of dust reddening, based on Gaia parallaxes and stellar photometry from Pan-STARRS 1 and 2MASS. This map covers the sky north of a decl. of -30\textdegree, out to a distance of a few kiloparsecs. This new map contains three major improvements over our previous work. First, the inclusion of Gaia parallaxes dramatically improves distance estimates to nearby stars. Second, we incorporate a spatial prior that correlates the dust density across nearby sightlines. This produces a smoother map, with more isotropic clouds and smaller distance uncertainties, particularly to clouds within the nearest kiloparsec. Third, we infer the dust density with a distance resolution that is four times finer than in our previous work, to accommodate the improvements in signal-to-noise enabled by the other improvements. As part of this work, we infer the distances, reddenings, and types of 799 million stars. (Our 3D dust map can be accessed at doi:10.7910/DVN/2EJ9TX or through the Python package dustmaps, while our catalog of stellar parameters can be accessed at doi:10.7910/DVN/AV9GXO. More information about the map, as well as an interactive viewer, can be found at argonaut.skymaps.info.) We obtain typical reddening uncertainties that are {$\sim$}30\% smaller than those reported in the Gaia DR2 catalog, reflecting the greater number of photometric passbands that enter into our analysis.},
  journal = {ApJ},
  keywords = {dustmaps,Gaia,Galaxy stellar content,Galaxy structure,Interstellar dust,Interstellar dust extinction,Interstellar reddening}
}

@article{Grevesse.Sauval1998,
  title = {Standard {{Solar Composition}}},
  author = {Grevesse, N. and Sauval, A. J.},
  year = {1998},
  month = may,
  volume = {85},
  pages = {161--174},
  issn = {0038-6308},
  doi = {10.1023/A:1005161325181},
  abstract = {We review the current status of our knowledge of the chemical composition of the Sun, essentially derived from the analysis of the solar photospheric spectrum. The comparison of solar and meteoritic abundances confirms that there is a very good agreement between the two sets of abundances. They are used to construct a Standard Abundance Distribution.},
  journal = {Space Sci. Rev.},
  keywords = {Meteorites: abundances,Solar spectroscopy,Sun: abundances}
}

@article{Hahnloser.Sarpeshkar.ea2000,
  title = {Digital Selection and Analogue Amplification Coexist in a Cortex-Inspired Silicon Circuit},
  author = {Hahnloser, Richard H. R. and Sarpeshkar, Rahul and Mahowald, Misha A. and Douglas, Rodney J. and Seung, H. Sebastian},
  year = {2000},
  month = jun,
  volume = {405},
  pages = {947--951},
  doi = {10.1038/35016072},
  abstract = {Digital circuits such as the flip-flop use feedback to achieve  multi-stability and nonlinearity to restore signals to logical levels, for example 0 and 1. Analogue feedback circuits are generally designed to operate linearly, so that signals are over a range, and the response is unique. By contrast, the response of cortical circuits to sensory stimulation can be both multistable and graded. We propose that the neocortex combines digital selection of an active set of neurons with analogue response by dynamically varying the positive feedback inherent in its recurrent connections. Strong positive feedback causes differential instabilities that drive the selection of a set of active neurons under the constraints embedded in the synaptic weights. Once selected, the active neurons generate weaker, stable feedback that provides analogue amplification of the input. Here we present our model of cortical processing as an electronic circuit that emulates this hybrid operation, and so is able to perform computations that are similar to stimulus selection, gain modulation and spatiotemporal pattern generation in the neocortex.},
  journal = {Nature}
}

@article{Halabi.Izzard.ea2017,
  title = {{{2DStars}}: {{A}} Two-Dimensional Stellar Evolution Code.},
  shorttitle = {{{2DStars}}},
  author = {Halabi, G. M. and Izzard, R. G. and Tout, C. A. and Jermyn, A. S. and Cannon, R.},
  year = {2017},
  volume = {88},
  pages = {319},
  abstract = {We introduce the 2DStars code, a new two-dimensional stellar evolution code under construction to model rotating stars. Most of our current understanding of stellar interiors and evolution is based largely on one-dimensional models. In these models, complex physical processes such as convection, rotation and magnetic fields are typically described by simplified approaches which rely on free parameters. Such parametrized descriptions have little predictive power and often fail to capture the physical nature of the underlying processes responsible for discrepancies between models and observations. Given the increasing computational power and algorithmic efficiency, multi-dimensional models are now timely and crucial in order to make progress in the field of stellar astrophysics and take full advantage of the unprecedented developments in observational astronomy, notably high-resolution spectroscopy, as well as present and future spectroscopic surveys.},
  journal = {Mem. Della Soc. Astron. Ital.},
  keywords = {Stars: evolution,Stars: interiors,Stars: rotation}
}

@article{Hall.Davies.ea2019,
  title = {Testing Asteroseismology with {{Gaia DR2}}: Hierarchical Models of the {{Red Clump}}},
  shorttitle = {Testing Asteroseismology with {{Gaia DR2}}},
  author = {Hall, Oliver J. and Davies, Guy R. and Elsworth, Yvonne P. and Miglio, Andrea and Bedding, Timothy R. and Brown, Anthony G. A. and Khan, Saniya and Hawkins, Keith and Garc{\'i}a, Rafael A. and Chaplin, William J. and North, Thomas S. H.},
  year = {2019},
  month = jul,
  volume = {486},
  pages = {3569--3585},
  issn = {0035-8711},
  doi = {10.1093/mnras/stz1092},
  abstract = {Asteroseismology provides fundamental stellar parameters independent of distance, but subject to systematics under calibration. Gaia DR2 has provided parallaxes for a billion stars, which are offset by a parallax zero-point ({$\varpi$}zp). Red Clump (RC) stars have a narrow spread in luminosity, thus functioning as standard candles to calibrate these systematics. This work measures how the magnitude and spread of the RC in the Kepler field are affected by changes to temperature and scaling relations for seismology, and changes to the parallax zero-point for Gaia. We use a sample of 5576 RC stars classified through asteroseismology. We apply hierarchical Bayesian latent variable models, finding the population-level properties of the RC with seismology, and use those as priors on Gaia parallaxes to find {$\varpi$}zp. We then find the position of the RC, using published values for {$\varpi$}zp. We find a seismic temperature-insensitive spread of the RC of \{{$\sim$} \}0.03 mag in the 2MASS K band and a larger and slightly temperature-dependent spread of \{{$\sim$} \}0.13 mag in the Gaia G band. This intrinsic dispersion in the K band provides a distance precision of \{{$\sim$} \} 1\{\{ per cent\}\} for RC stars. Using Gaia data alone, we find a mean zero-point of -41{$\pm$} 10 {$\mu$} as. This offset yields RC absolute magnitudes of -1.634 {$\pm$} 0.018 in K and 0.546 {$\pm$} 0.016 in G. Obtaining these same values through seismology would require a global temperature shift of \{{$\sim$} \}-70 K, which is compatible with known systematics in spectroscopy.},
  journal = {MNRAS},
  keywords = {asteroseismology,parallaxes,stars: fundamental parameters,stars: statistics}
}

@article{Hawkins.Leistedt.ea2017,
  title = {Red Clump Stars and {{Gaia}}: Calibration of the Standard Candle Using a Hierarchical Probabilistic Model},
  shorttitle = {Red Clump Stars and {{Gaia}}},
  author = {Hawkins, Keith and Leistedt, Boris and Bovy, Jo and Hogg, David W.},
  year = {2017},
  month = oct,
  volume = {471},
  pages = {722--729},
  issn = {0035-8711},
  doi = {10.1093/mnras/stx1655},
  abstract = {Distances to individual stars in our own Galaxy are critical in order to  piece together the nature of its velocity and spatial structure. Core helium burning red clump (RC) stars have similar luminosities, are abundant throughout the Galaxy and thus constitute good standard candles. We build a hierarchical probabilistic model to quantify the quality of RC stars as standard candles using parallax measurements from the first Gaia data release. A unique aspect of our methodology is to fully account for (and marginalize over) parallax, photometry and dust correction uncertainties, which lead to more robust results than standard approaches. We determine the absolute magnitude and intrinsic dispersion of the RC in 2MASS bands J, H, Ks, Gaia G band and WISE bands W1, W2, W3 and W4. We find that the absolute magnitude of the RC is -1.61 {$\pm$} 0.01 (in Ks), +0.44 {$\pm$} 0.01 (in G), -0.93 {$\pm$} 0.01 (in J), -1.46 {$\pm$} 0.01 (in H), -1.68 {$\pm$} 0.02 (in W1), -1.69 {$\pm$} 0.02 (in W2), -1.67 {$\pm$} 0.02 (in W3) and -1.76 {$\pm$} 0.01 mag (in W4). The mean intrinsic dispersion is {$\sim$}0.17 {$\pm$} 0.03 mag across all bands (yielding a typical distance precision of {$\sim$}8 per cent). Thus RC stars are reliable and precise standard candles. In addition, we have also re-calibrated the zero-point of the absolute magnitude of the RC in each band, which provides a benchmark for future studies to estimate distances to RC stars. Finally, the parallax error shrinkage in the hierarchical model outlined in this work can be used to obtain more precise parallaxes than Gaia for the most distant RC stars across the Galaxy.},
  journal = {MNRAS},
  keywords = {Stars: distances,Stars: fundamental parameters,Stars: statistics}
}

@book{Haykin2007,
  title = {Neural Networks: {{A}} Comprehensive Foundation (3rd Edition)},
  author = {Haykin, Simon},
  year = {2007},
  publisher = {{Prentice-Hall, Inc.}},
  address = {{Upper Saddle River}, {NJ}},
  isbn = {0-13-147139-2}
}

@article{Hekker.Elsworth.ea2012,
  title = {Solar-like Oscillations in Red Giants Observed with {{Kepler}}: Influence of Increased Timespan on Global Oscillation Parameters},
  shorttitle = {Solar-like Oscillations in Red Giants Observed with {{Kepler}}},
  author = {Hekker, S. and Elsworth, Y. and Mosser, B. and Kallinger, T. and Chaplin, W. J. and De Ridder, J. and Garc{\'i}a, R. A. and Stello, D. and Clarke, B. D. and Hall, J. R. and Ibrahim, K. A.},
  year = {2012},
  month = aug,
  volume = {544},
  pages = {A90},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201219328},
  abstract = {Context. The length of the asteroseismic timeseries obtained from the  Kepler satellite analysed here span 19 months. Kepler provides the longest continuous timeseries currently available, which calls for a study of the influence of the increased timespan on the accuracy and precision of the obtained results. Aims: We aim to investigate how the increased timespan influences the detectability of the oscillation modes, and the absolute values and uncertainties of the global oscillation parameters, i.e., frequency of maximum oscillation power, {$\nu$}max, and large frequency separation between modes of the same degree and consecutive orders, {$\langle$} {$\Delta\nu$} {$\rangle$} .  Methods: We use published methods to derive {$\nu$}max and {$\langle$} {$\Delta\nu$} {$\rangle$} for timeseries ranging from 50 to 600 days and compare these results as a function of method, timespan and {$\langle$} {$\Delta\nu$} {$\rangle$} . Results: We find that in general a minimum of the order of 400 day long timeseries are necessary to obtain reliable results for the global oscillation parameters in more than 95\% of the stars, but this does depend on {$\langle$} {$\Delta\nu$} {$\rangle$} . In a statistical sense the quoted uncertainties seem to provide a reasonable indication of the precision of the obtained results in short (50-day) runs, they do however seem to be overestimated for results of longer runs. Furthermore, the different definitions of the global parameters used in the different methods have non-negligible effects on the obtained values. Additionally, we show that there is a correlation between {$\nu$}max and the flux variance. Conclusions: We conclude that longer timeseries improve the likelihood to detect oscillations with automated codes (from \textasciitilde 60\% in 50 day runs to {$>$}95\% in 400 day runs with a slight method dependence) and the precision of the obtained global oscillation parameters. The trends suggest that the improvement will continue for even longer timeseries than the 600 days considered here, with a reduction in the median absolute deviation of more than a factor of 10 for an increase in timespan from 50 to 2000 days (the currently foreseen length of the mission). This work shows that global parameters determined with high precision - thus from long datasets - using different definitions can be used to identify the evolutionary state of the stars. Values of the global oscillation parameters can be obtained from the authors upon request.},
  journal = {A\&A},
  keywords = {asteroseismology,red giants,stars: interiors,stars: late-type,stars: oscillations,techniques: photometric}
}

@article{Hendriks.Aerts2019,
  title = {Deep {{Learning Applied}} to the {{Asteroseismic Modeling}} of {{Stars}} with {{Coherent Oscillation Modes}}},
  author = {Hendriks, L. and Aerts, C.},
  year = {2019},
  month = oct,
  volume = {131},
  pages = {108001},
  issn = {0004-6280},
  doi = {10.1088/1538-3873/aaeeec},
  abstract = {We develop a novel method based on machine-learning principles to  achieve optimal initiation of CPU-intensive computations for forward asteroseismic modeling in a multi-dimensional parameter space. A deep neural network is trained on a precomputed asteroseismology grid containing about 62 million coherent oscillation-mode frequencies derived from stellar evolution models. These models are representative of the core-hydrogen-burning stage of intermediate-mass and high-mass stars. The evolution models constitute a 6D parameter space and their predicted low-degree pressure- and gravity-mode oscillations are scanned using a genetic algorithm. A software pipeline is created to find the best-fitting stellar parameters for a given set of observed oscillation frequencies. The proposed method finds the optimal regions in the 6D parameter space in less than a minute, hence providing the optimal starting point for further and more detailed forward asteroseismic modeling in a high-dimensional context. We test and apply the method to seven pulsating stars that were previously modeled asteroseismically by classical grid-based forward modeling based on a {$\chi$} 2 statistic, and obtain good agreement with past results. Our deep-learning methodology opens up the application of asteroseismic modeling in +6D parameter space for thousands of stars pulsating in coherent modes with long lifetimes observed by the Kepler space telescope and to be discovered with the TESS and PLATO space missions, while applications so far have been done star-by-star for only a handful of cases. Our method is open source and can be freely used by anyone.3},
  journal = {PASP}
}

@article{Hoffman.Gelman2014,
  title = {The {{No}}-{{U}}-Turn Sampler: Adaptively Setting Path Lengths in {{Hamiltonian Monte Carlo}}},
  shorttitle = {The {{No}}-{{U}}-Turn Sampler},
  author = {Hoffman, Matthew D. and Gelman, Andrew},
  year = {2014},
  month = jan,
  volume = {15},
  pages = {1593--1623},
  issn = {1532-4435},
  abstract = {Hamiltonian Monte Carlo (HMC) is a Markov chain Monte Carlo (MCMC) algorithm that avoids the random walk behavior and sensitivity to correlated parameters that plague many MCMC methods by taking a series of steps informed by first-order gradient information. These features allow it to converge to high-dimensional target distributions much more quickly than simpler methods such as random walk Metropolis or Gibbs sampling. However, HMC's performance is highly sensitive to two user-specified parameters: a step size {$\epsilon$} and a desired number of steps L. In particular, if L is too small then the algorithm exhibits undesirable random walk behavior, while if L is too large the algorithm wastes computation. We introduce the No-U-Turn Sampler (NUTS), an extension to HMC that eliminates the need to set a number of steps L. NUTS uses a recursive algorithm to build a set of likely candidate points that spans a wide swath of the target distribution, stopping automatically when it starts to double back and retrace its steps. Empirically, NUTS performs at least as efficiently as (and sometimes more effciently than) a well tuned standard HMC method, without requiring user intervention or costly tuning runs. We also derive a method for adapting the step size parameter {$\epsilon$} on the fly based on primal-dual averaging. NUTS can thus be used with no hand-tuning at all, making it suitable for applications such as BUGS-style automatic inference engines that require efficient "turnkey" samplers.},
  journal = {J. Mach. Learn. Res.},
  keywords = {adaptive Monte Carlo,Bayesian inference,dual averaging,Hamiltonian Monte Carlo,Markov chain Monte Carlo},
  number = {1}
}

@article{Hogg.Bovy.ea2010,
  ids = {Hogg.Bovy.ea2010a},
  title = {Data Analysis Recipes: {{Fitting}} a Model to Data},
  shorttitle = {Data Analysis Recipes},
  author = {Hogg, David W. and Bovy, Jo and Lang, Dustin},
  year = {2010},
  month = aug,
  abstract = {We go through the many considerations involved in fitting a model to data, using as an example the fit of a straight line to a set of points in a two-dimensional plane. Standard weighted least-squares fitting is only appropriate when there is a dimension along which the data points have negligible uncertainties, and another along which all the uncertainties can be described by Gaussians of known variance; these conditions are rarely met in practice. We consider cases of general, heterogeneous, and arbitrarily covariant two-dimensional uncertainties, and situations in which there are bad data (large outliers), unknown uncertainties, and unknown but expected intrinsic scatter in the linear relationship being fit. Above all we emphasize the importance of having a "generative model" for the data, even an approximate one. Once there is a generative model, the subsequent fitting is non-arbitrary because the model permits direct computation of the likelihood of the parameters or the posterior probability distribution. Construction of a posterior probability distribution is indispensible if there are "nuisance parameters" to marginalize away.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1008.4686},
  eprint = {1008.4686},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Physics - Data Analysis,Statistics and Probability},
  primaryclass = {astro-ph.IM}
}

@article{Hogg.Foreman-Mackey2018,
  title = {Data {{Analysis Recipes}}: {{Using Markov Chain Monte Carlo}}},
  shorttitle = {Data {{Analysis Recipes}}},
  author = {Hogg, David W. and {Foreman-Mackey}, Daniel},
  year = {2018},
  month = may,
  volume = {236},
  pages = {11},
  issn = {0067-0049},
  doi = {10.3847/1538-4365/aab76e},
  abstract = {Markov Chain Monte Carlo (MCMC) methods for sampling probability density functions (combined with abundant computational resources) have transformed the sciences, especially in performing probabilistic inferences, or fitting models to data. In this primarily pedagogical contribution, we give a brief overview of the most basic MCMC method and some practical advice for the use of MCMC in real inference problems. We give advice on method choice, tuning for performance, methods for initialization, tests of convergence, troubleshooting, and use of the chain output to produce or report parameter estimates with associated uncertainties. We argue that autocorrelation time is the most important test for convergence, as it directly connects to the uncertainty on the sampling estimate of any quantity of interest. We emphasize that sampling is a method for doing integrals; this guides our thinking about how MCMC output is best used. .},
  journal = {ApJS},
  keywords = {methods: data analysis,methods: numerical,methods: statistical}
}

@article{Hogg.Myers.ea2010,
  title = {Inferring the {{Eccentricity Distribution}}},
  author = {Hogg, David W. and Myers, Adam D. and Bovy, Jo},
  year = {2010},
  month = dec,
  volume = {725},
  pages = {2166--2175},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/725/2/2166},
  abstract = {Standard maximum-likelihood estimators for binary-star and exoplanet eccentricities are biased high, in the sense that the estimated eccentricity tends to be larger than the true eccentricity. As with most non-trivial observables, a simple histogram of estimated eccentricities is not a good estimate of the true eccentricity distribution. Here, we develop and test a hierarchical probabilistic method for performing the relevant meta-analysis, that is, inferring the true eccentricity distribution, taking as input the likelihood functions for the individual star eccentricities, or samplings of the posterior probability distributions for the eccentricities (under a given, uninformative prior). The method is a simple implementation of a hierarchical Bayesian model; it can also be seen as a kind of heteroscedastic deconvolution. It can be applied to any quantity measured with finite precision\textemdash other orbital parameters, or indeed any astronomical measurements of any kind, including magnitudes, distances, or photometric redshifts\textemdash so long as the measurements have been communicated as a likelihood function or a posterior sampling.},
  journal = {ApJ},
  keywords = {binaries: general,methods: data analysis,methods: statistical,planetary systems,planets and satellites: fundamental parameters,stars: kinematics and dynamics}
}

@article{Hogg2012,
  ids = {Hogg2012a},
  title = {Data Analysis Recipes: {{Probability}} Calculus for Inference},
  shorttitle = {Data Analysis Recipes},
  author = {Hogg, David W.},
  year = {2012},
  month = may,
  abstract = {In this pedagogical text aimed at those wanting to start thinking about or brush up on probabilistic inference, I review the rules by which probability distribution functions can (and cannot) be combined. I connect these rules to the operations performed in probabilistic data analysis. Dimensional analysis is emphasized as a valuable tool for helping to construct non-wrong probabilistic statements. The applications of probability calculus in constructing likelihoods, marginalized likelihoods, posterior probabilities, and posterior predictions are all discussed.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1205.4446},
  eprint = {1205.4446},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Physics - Data Analysis,Statistics and Probability},
  primaryclass = {physics.data-an}
}

@article{Hon.Bellinger.ea2020,
  title = {Asteroseismic Inference of Subgiant Evolutionary Parameters with Deep Learning},
  author = {Hon, Marc and Bellinger, Earl P. and Hekker, Saskia and Stello, Dennis and Kuszlewicz, James S.},
  year = {2020},
  month = sep,
  volume = {499},
  pages = {2445--2461},
  issn = {0035-8711},
  doi = {10.1093/mnras/staa2853},
  abstract = {With the observations of an unprecedented number of oscillating subgiant stars expected from NASA's TESS mission, the asteroseismic characterization of subgiant stars will be a vital task for stellar population studies and for testing our theories of stellar evolution. To determine the fundamental properties of a large sample of subgiant stars efficiently, we developed a deep learning method that estimates distributions of fundamental parameters like age and mass over a wide range of input physics by learning from a grid of stellar models varied in eight physical parameters. We applied our method to four Kepler subgiant stars and compare our results with previously determined estimates. Our results show good agreement with previous estimates for three of them (KIC 11026764, KIC 10920273, KIC 11395018). With the ability to explore a vast range of stellar parameters, we determine that the remaining star, KIC 10005473, is likely to have an age 1 Gyr younger than its previously determined estimate. Our method also estimates the efficiency of overshooting, undershooting, and microscopic diffusion processes, from which we determined that the parameters governing such processes are generally poorly constrained in subgiant models. We further demonstrate our method's utility for ensemble asteroseismology by characterizing a sample of 30 Kepler subgiant stars, where we find a majority of our age, mass, and radius estimates agree within uncertainties from more computationally expensive grid-based modelling techniques.},
  journal = {Monthly Notices of the Royal Astronomical Society},
  keywords = {asteroseismology,methods: data analysis,stars: evolution,stars: oscillations}
}

@article{Hon.Stello.ea2017,
  title = {Deep Learning Classification in Asteroseismology},
  author = {Hon, Marc and Stello, Dennis and Yu, Jie},
  year = {2017},
  month = aug,
  volume = {469},
  pages = {4578--4583},
  issn = {0035-8711, 1365-2966},
  doi = {10.1093/mnras/stx1174},
  abstract = {In the power spectra of oscillating red giants, there are visually distinct features defining stars ascending the red giant branch from those that have commenced helium core burning. We train a 1D convolutional neural network by supervised learning to automatically learn these visual features from images of folded oscillation spectra. By training and testing on Kepler red giants, we achieve an accuracy of up to 99 per cent in separating helium-burning red giants from those ascending the red giant branch. The convolutional neural network additionally shows capability in accurately predicting the evolutionary states of 5379 previously unclassified Kepler red giants, by which we now have greatly increased the number of classified stars.},
  journal = {MNRAS},
  keywords = {asteroseismology,deep learning,machine learning,red giants},
  language = {en},
  number = {4}
}

@article{Hon.Stello.ea2018,
  title = {Detecting {{Solar}}-like {{Oscillations}} in {{Red Giants}} with {{Deep Learning}}},
  author = {Hon, Marc and Stello, Dennis and Zinn, Joel C.},
  year = {2018},
  month = may,
  volume = {859},
  pages = {64},
  issn = {1538-4357},
  doi = {10.3847/1538-4357/aabfdb},
  abstract = {Time-resolved photometry of tens of thousands of red giant stars from space missions like Kepler and K2 has created the need for automated asteroseismic analysis methods. The first and most fundamental step in such analysis is to identify which stars show oscillations. It is critical that this step be performed with no, or little, detection bias, particularly when performing subsequent ensemble analyses that aim to compare the properties of observed stellar populations with those from galactic models. However, an efficient, automated solution to this initial detection step still has not been found, meaning that expert visual inspection of data from each star is required to obtain the highest level of detections. Hence, to mimic how an expert eye analyzes the data, we use supervised deep learning to not only detect oscillations in red giants, but also to predict the location of the frequency at maximum power, {$\nu$}max, by observing features in 2D images of power spectra. By training on Kepler data, we benchmark our deep-learning classifier against K2 data that are given detections by the expert eye, achieving a detection accuracy of 98\% on K2 Campaign 6 stars and a detection accuracy of 99\% on K2 Campaign 3 stars. We further find that the estimated uncertainty of our deep-learning-based {$\nu$}max predictions is about 5\%. This is comparable to human-level performance using visual inspection. When examining outliers, we find that the deep-learning results are more likely to provide robust {$\nu$}max estimates than the classical model-fitting method.},
  journal = {ApJ},
  keywords = {asteroseismology,deep learning,machine learning,red giants},
  language = {en},
  number = {1}
}

@article{Hon.Stello.ea2018a,
  title = {Deep Learning Classification in Asteroseismology Using an Improved Neural Network: Results on 15 000 {{Kepler}} Red Giants and Applications to {{K2}} and {{TESS}} Data},
  shorttitle = {Deep Learning Classification in Asteroseismology Using an Improved Neural Network},
  author = {Hon, Marc and Stello, Dennis and Yu, Jie},
  year = {2018},
  month = may,
  volume = {476},
  pages = {3233--3244},
  issn = {0035-8711},
  doi = {10.1093/mnras/sty483},
  abstract = {Deep learning in the form of 1D convolutional neural networks have  previously been shown to be capable of efficiently classifying the evolutionary state of oscillating red giants into red giant branch stars and helium-core burning stars by recognizing visual features in their asteroseismic frequency spectra. We elaborate further on the deep learning method by developing an improved convolutional neural network classifier. To make our method useful for current and future space missions such as K2, TESS, and PLATO, we train classifiers that are able to classify the evolutionary states of lower frequency resolution spectra expected from these missions. Additionally, we provide new classifications for 8633 Kepler red giants, out of which 426 have previously not been classified using asteroseismology. This brings the total to 14983 Kepler red giants classified with our new neural network. We also verify that our classifiers are remarkably robust to suboptimal data, including low signal-to-noise and incorrect training truth labels.},
  journal = {MNRAS},
  keywords = {asteroseismology,methods: data analysis,stars: evolution,stars: oscillations,stars: statistics}
}

@article{Houdek.Gough2007,
  title = {An Asteroseismic Signature of Helium Ionization},
  author = {Houdek, G. and Gough, D. O.},
  year = {2007},
  month = mar,
  volume = {375},
  pages = {861--880},
  doi = {10.1111/j.1365-2966.2006.11325.x},
  abstract = {We investigate the influence of the ionization of helium on the low-degree acoustic oscillation frequencies in model solar-type stars. The signature in the oscillation frequencies characterizing the ionization-induced depression of the first adiabatic exponent {$\gamma$} is a superposition of two decaying periodic functions of frequency {$\nu$}, with `frequencies' that are approximately twice the acoustic depths of the centres of the HeI and HeII ionization regions. That variation is probably best exhibited in the second frequency difference {$\Delta$}2{$\nu$}n,l {$\equiv$} {$\nu$}n-1,l - 2{$\nu$}n,l + {$\nu$}n+1,l. We show how an analytic approximation to the variation of {$\gamma$} leads to a simple representation of this oscillatory contribution to {$\Delta$}2{$\nu$} which can be used to characterize the {$\gamma$} variation, our intention being to use it as a seismic diagnostic of the helium abundance of the star. We emphasize that the objective is to characterize {$\gamma$}, not merely to find a formula for {$\Delta$}2{$\nu$} that reproduces the data.},
  journal = {MNRAS},
  keywords = {stars: abundances,stars: interiors,stars: oscillations,Sun: abundances,Sun: oscillations}
}

@article{Howe.Chaplin.ea2020,
  title = {Solar Cycle Variation of {$N$}max in Helioseismic Data and Its Implications for Asteroseismology},
  author = {Howe, Rachel and Chaplin, William J. and Basu, Sarbani and Ball, Warrick H. and Davies, Guy R. and Elsworth, Yvonne and Hale, Steven J. and Miglio, Andrea and Nielsen, Martin Bo and Viani, Lucas S.},
  year = {2020},
  month = mar,
  volume = {493},
  pages = {L49-L53},
  issn = {0035-8711},
  doi = {10.1093/mnrasl/slaa006},
  abstract = {The frequency, {$\nu$}max, at which the envelope of pulsation  power peaks for solar-like oscillators is an important quantity in asteroseismology. We measure {$\nu$}max for the Sun using 25 yr of Sun-as-a-star Doppler velocity observations with the Birmingham Solar-Oscillations Network (BiSON), by fitting a simple model to binned power spectra of the data. We also apply the fit to Sun-as-a-star Doppler velocity data from Global Oscillation Network Group and Global Oscillations at Low Frequency, and photometry data from VIRGO/SPM on the ESA/NASA SOHO spacecraft. We discover a weak but nevertheless significant positive correlation of the solar {$\nu$}max with solar activity. The uncovered shift between low and high activity, of {$\sim$}eq 25 {$\mu$} Hz, translates to an uncertainty of 0.8 per cent in radius and 2.4 per cent in mass, based on direct use of asteroseismic scaling relations calibrated to the Sun. The mean {$\nu$}max in the different data sets is also clearly offset in frequency. Our results flag the need for caution when using {$\nu$}max in asteroseismology.},
  journal = {MNRAS},
  keywords = {asteroseismology,helioseismology,Sun: activity,Sun: helioseismology}
}

@article{Huber.Bedding.ea2011,
  title = {Testing {{Scaling Relations}} for {{Solar}}-like {{Oscillations}} from the {{Main Sequence}} to {{Red Giants Using Kepler Data}}},
  author = {Huber, D. and Bedding, T. R. and Stello, D. and Hekker, S. and Mathur, S. and Mosser, B. and Verner, G. A. and Bonanno, A. and Buzasi, D. L. and Campante, T. L. and Elsworth, Y. P. and Hale, S. J. and Kallinger, T. and Silva Aguirre, V. and Chaplin, W. J. and De Ridder, J. and Garc{\'i}a, R. A. and Appourchaux, T. and Frandsen, S. and Houdek, G. and {Molenda-{\.Z}akowicz}, J. and Monteiro, M. J. P. F. G. and {Christensen-Dalsgaard}, J. and Gilliland, R. L. and Kawaler, S. D. and Kjeldsen, H. and Broomhall, A. M. and Corsaro, E. and Salabert, D. and Sanderfer, D. T. and Seader, S. E. and Smith, J. C.},
  year = {2011},
  month = dec,
  volume = {743},
  pages = {143},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/743/2/143},
  abstract = {We have analyzed solar-like oscillations in \textasciitilde 1700 stars observed by the  Kepler Mission, spanning from the main sequence to the red clump. Using evolutionary models, we test asteroseismic scaling relations for the frequency of maximum power ({$\nu$}max), the large frequency separation ({$\Delta\nu$}), and oscillation amplitudes. We show that the difference of the {$\Delta\nu$}-{$\nu$}max relation for unevolved and evolved stars can be explained by different distributions in effective temperature and stellar mass, in agreement with what is expected from scaling relations. For oscillation amplitudes, we show that neither (L/M) s scaling nor the revised scaling relation by Kjeldsen \& Bedding is accurate for red-giant stars, and demonstrate that a revised scaling relation with a separate luminosity-mass dependence can be used to calculate amplitudes from the main sequence to red giants to a precision of \textasciitilde 25\%. The residuals show an offset particularly for unevolved stars, suggesting that an additional physical dependency is necessary to fully reproduce the observed amplitudes. We investigate correlations between amplitudes and stellar activity, and find evidence that the effect of amplitude suppression is most pronounced for subgiant stars. Finally, we test the location of the cool edge of the instability strip in the Hertzsprung-Russell diagram using solar-like oscillations and find the detections in the hottest stars compatible with a domain of hybrid stochastically excited and opacity driven pulsation.},
  journal = {ApJ},
  keywords = {stars: late-type,stars: oscillations,techniques: photometric}
}

@article{Huber.Chaplin.ea2019,
  title = {A {{Hot Saturn Orbiting}} an {{Oscillating Late Subgiant Discovered}} by {{TESS}}},
  author = {Huber, Daniel and Chaplin, William J. and Chontos, Ashley and Kjeldsen, Hans and {Christensen-Dalsgaard}, J{\o}rgen and Bedding, Timothy R. and Ball, Warrick and Brahm, Rafael and Espinoza, Nestor and Henning, Thomas and Jord{\'a}n, Andr{\'e}s and Sarkis, Paula and Knudstrup, Emil and Albrecht, Simon and Grundahl, Frank and Fredslund Andersen, Mads and Pall{\'e}, Pere L. and Crossfield, Ian and Fulton, Benjamin and Howard, Andrew W. and Isaacson, Howard T. and Weiss, Lauren M. and Handberg, Rasmus and Lund, Mikkel N. and Serenelli, Aldo M. and R{\o}rsted Mosumgaard, Jakob and Stokholm, Amalie and Bieryla, Allyson and Buchhave, Lars A. and Latham, David W. and Quinn, Samuel N. and Gaidos, Eric and Hirano, Teruyuki and Ricker, George R. and Vanderspek, Roland K. and Seager, Sara and Jenkins, Jon M. and Winn, Joshua N. and Antia, H. M. and Appourchaux, Thierry and Basu, Sarbani and Bell, Keaton J. and Benomar, Othman and Bonanno, Alfio and Buzasi, Derek L. and Campante, Tiago L. and {\c C}elik Orhan, Z. and Corsaro, Enrico and Cunha, Margarida S. and Davies, Guy R. and Deheuvels, Sebastien and Grunblatt, Samuel K. and Hasanzadeh, Amir and Di Mauro, Maria Pia and Garc{\'i}a, Rafael A. and Gaulme, Patrick and Girardi, L{\'e}o and Guzik, Joyce A. and Hon, Marc and Jiang, Chen and Kallinger, Thomas and Kawaler, Steven D. and Kuszlewicz, James S. and Lebreton, Yveline and Li, Tanda and Lucas, Miles and Lundkvist, Mia S. and Mann, Andrew W. and Mathis, St{\'e}phane and Mathur, Savita and Mazumdar, Anwesh and Metcalfe, Travis S. and Miglio, Andrea and Monteiro, M{\'a}rio J. P. F. G. and Mosser, Benoit and Noll, Anthony and Nsamba, Benard and Ong, Jia Mian Joel and {\"O}rtel, S. and Pereira, Filipe and Ranadive, Pritesh and R{\'e}gulo, Clara and Rodrigues, Tha{\'i}se S. and Roxburgh, Ian W. and Silva Aguirre, Victor and Smalley, Barry and Schofield, Mathew and Sousa, S{\'e}rgio G. and Stassun, Keivan G. and Stello, Dennis and Tayar, Jamie and White, Timothy R. and Verma, Kuldeep and Vrard, Mathieu and Y{\i}ld{\i}z, M. and Baker, David and Bazot, Micha{\"e}l and Beichmann, Charles and Bergmann, Christoph and Bugnet, Lisa and Cale, Bryson and Carlino, Roberto and Cartwright, Scott M. and Christiansen, Jessie L. and Ciardi, David R. and Creevey, Orlagh and Dittmann, Jason A. and Do Nascimento, Jr., Jose-Dias and Van Eylen, Vincent and F{\"u}r{\'e}sz, Gabor and Gagn{\'e}, Jonathan and Gao, Peter and Gazeas, Kosmas and Giddens, Frank and Hall, Oliver J. and Hekker, Saskia and Ireland, Michael J. and Latouf, Natasha and LeBrun, Danny and Levine, Alan M. and Matzko, William and Natinsky, Eva and Page, Emma and Plavchan, Peter and {Mansouri-Samani}, Masoud and McCauliff, Sean and Mullally, Susan E. and Orenstein, Brendan and Garcia Soto, Aylin and Paegert, Martin and {van Saders}, Jennifer L. and Schnaible, Chloe and Soderblom, David R. and Szab{\'o}, R{\'o}bert and Tanner, Angelle and Tinney, C. G. and Teske, Johanna and Thomas, Alexandra and Trampedach, Regner and Wright, Duncan and Yuan, Thomas T. and Zohrabi, Farzaneh},
  year = {2019},
  month = jun,
  volume = {157},
  pages = {245},
  doi = {10.3847/1538-3881/ab1488},
  abstract = {We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V = 8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 {$\mu$}Hz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2 minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (R {$\star$} = 2.943 {$\pm$} 0.064 R {$\odot$}), mass (M {$\star$} = 1.212 {$\pm$} 0.074 M {$\odot$}), and age (4.9 {$\pm$} 1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a ``hot Saturn'' (R p = 9.17 {$\pm$} 0.33 R {$\oplus$}) with an orbital period of {$\sim$}14.3 days, irradiance of F = 343 {$\pm$} 24 F {$\oplus$}, and moderate mass (M p = 60.5 {$\pm$} 5.7 M {$\oplus$}) and density ({$\rho$} p = 0.431 {$\pm$} 0.062 g cm-3). The properties of HD 221416 b show that the host-star metallicity-planet mass correlation found in sub-Saturns (4-8 R {$\oplus$}) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to {$\sim$}15\%, HD 221416 b is one of the best characterized Saturn-size planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology.},
  journal = {AJ},
  keywords = {asteroseismology,planets and satellites: fundamental parameters,planets and satellites: individual: HD 221416 b,stars: fundamental parameters,techniques: photometric}
}

@article{Huber.Stello.ea2009,
  title = {Automated Extraction of Oscillation Parameters for {{Kepler}} Observations of Solar-Type Stars},
  author = {Huber, D. and Stello, D. and Bedding, T. R. and Chaplin, W. J. and Arentoft, T. and Quirion, P.-O. and Kjeldsen, H.},
  year = {2009},
  month = oct,
  volume = {160},
  pages = {74},
  issn = {1021-2043},
  abstract = {The recent launch of the Kepler space telescope brings the opportunity  to study oscillations systematically in large numbers of solar-like stars. In the framework of the asteroFLAG project, we have developed an automated pipeline to estimate global oscillation parameters, such as the frequency of maximum power ({$\nu$}max ) and the large frequency spacing ({$\Delta\nu$}), for a large number of time series. We present an effective method based on the autocorrelation function to find excess power and use a scaling relation to estimate granulation timescales as initial conditions for background modelling. We derive reliable uncertainties for {$\nu$}max and {$\Delta\nu$} through extensive simulations. We have tested the pipeline on about 2000 simulated Kepler stars with magnitudes of V \texttildelow{} 7-12 and were able to correctly determine {$\nu$}max and {$\Delta\nu$} for about half of the sample. For about 20\%, the returned large frequency spacing is accurate enough to determine stellar radii to a 1\% precision. We conclude that the methods presented here are a promising approach to process the large amount of data expected from Kepler.},
  journal = {Commun. Asteroseismol.},
  keywords = {asteroseismology,Kepler}
}

@article{Huber.Zinn.ea2017,
  title = {Asteroseismology and {{Gaia}}: {{Testing Scaling Relations Using}} 2200 {{Kepler}}  {{Stars}} with {{TGAS Parallaxes}}},
  shorttitle = {Asteroseismology and {{Gaia}}},
  author = {Huber, Daniel and Zinn, Joel and {Bojsen-Hansen}, Mathias and Pinsonneault, Marc and Sahlholdt, Christian and Serenelli, Aldo and Silva Aguirre, Victor and Stassun, Keivan and Stello, Dennis and Tayar, Jamie and Bastien, Fabienne and Bedding, Timothy R. and Buchhave, Lars A. and Chaplin, William J. and Davies, Guy R. and Garc{\'i}a, Rafael A. and Latham, David W. and Mathur, Savita and Mosser, Benoit and Sharma, Sanjib},
  year = {2017},
  month = aug,
  volume = {844},
  pages = {102},
  doi = {10.3847/1538-4357/aa75ca},
  abstract = {We present a comparison of parallaxes and radii from asteroseismology  and Gaia DR1 (TGAS) for 2200 Kepler stars spanning from the main sequence to the red-giant branch. We show that previously identified offsets between TGAS parallaxes and distances derived from asteroseismology and eclipsing binaries have likely been overestimated for parallaxes {$\lessequivlnt$} 5\{--\}10 mas ({$\approx$}90\%-98\% of the TGAS sample). The observed differences in our sample can furthermore be partially compensated by adopting a hotter \{T\}\{eff\} scale (such as the infrared flux method) instead of spectroscopic temperatures for dwarfs and subgiants. Residual systematic differences are at the {$\approx$}2\% level in parallax across three orders of magnitude. We use TGAS parallaxes to empirically demonstrate that asteroseismic radii are accurate to {$\approx$}5\% or better for stars between {$\approx$} 0.8\{--\}8 \{R\}{$\odot$} . We find no significant offset for main-sequence ({$\lessequivlnt$} 1.5 \{R\}{$\odot$} ) and low-luminosity RGB stars ({$\approx$}3-8 \{R\}{$\odot$} ), but seismic radii appear to be systematically underestimated by {$\approx$}5\% for subgiants ({$\approx$}1.5-3 \{R\}{$\odot$} ). We find no systematic errors as a function of metallicity between [\{Fe\}/\{\{H\}\}]{$\approx$} -0.8 to +0.4 dex, and show tentative evidence that corrections to the scaling relation for the large frequency separation (\{\{{$\Delta$} \}\}{$\nu$} ) improve the agreement with TGAS for RGB stars. Finally, we demonstrate that beyond {$\approx$} 3 \{kpc\} asteroseismology will provide more precise distances than end-of-mission Gaia data, highlighting the synergy and complementary nature of Gaia and asteroseismology for studying galactic stellar populations.},
  journal = {ApJ},
  keywords = {parallaxes,stars: distances,stars: fundamental parameters,stars: late-type,stars: oscillations,techniques: photometric}
}

@article{Iben.Ehrman1962,
  title = {The {{Internal Structure}} of {{Middle Main}}-{{Sequence Stars}}.},
  author = {Iben, Jr., Icko and Ehrman, John R.},
  year = {1962},
  month = may,
  volume = {135},
  pages = {770},
  doi = {10.1086/147320},
  abstract = {Abstract image available at:  http://adsabs.harvard.edu/abs/1962ApJ...135..770I},
  journal = {ApJ}
}

@article{Izotov.Thuan2010,
  title = {The {{Primordial Abundance}} of {{4He}}: {{Evidence}} for {{Non}}-{{Standard Big Bang Nucleosynthesis}}},
  shorttitle = {The {{Primordial Abundance}} of {{4He}}},
  author = {Izotov, Yuri I. and Thuan, Trinh X.},
  year = {2010},
  month = feb,
  volume = {710},
  pages = {L67-L71},
  doi = {10.1088/2041-8205/710/1/L67},
  abstract = {We present a new determination of the primordial helium mass fraction  Yp , based on 93 spectra of 86 low-metallicity extragalactic H II regions, and taking into account the latest developments concerning systematic effects. These include collisional and fluorescent enhancements of He I recombination lines, underlying He I stellar absorption lines, collisional and fluorescent excitation of hydrogen lines, and temperature and ionization structure of the H II region. Using Monte Carlo methods to solve simultaneously for the above systematic effects, we find the best value to be Yp = 0.2565 {$\pm$} 0.0010 (stat.) {$\pm$} 0.0050 (syst.). This value is higher at the 2{$\sigma$} level than the value given by standard big bang nucleosynthesis, implying deviations from it. The effective number of light neutrino species N {$\nu$} is equal to 3.68+0.80 -0.70 (2{$\sigma$}) and 3.80+0.80 -0.70 (2{$\sigma$}) for a neutron lifetime {$\tau$} n equal to 885.4 {$\pm$} 0.9 s and 878.5 {$\pm$} 0.8 s, respectively, i.e., it is larger than the experimental value of 2.993 {$\pm$} 0.011.},
  journal = {Astrophys. J. Lett.},
  keywords = {galaxies: abundances,galaxies: irregular,galaxies: ISM,ISM: abundances}
}

@article{Kahn1961,
  title = {Sound {{Waves Trapped}} in the {{Solar Atmosphere}}.},
  author = {Kahn, F. D.},
  year = {1961},
  month = sep,
  volume = {134},
  pages = {343},
  doi = {10.1086/147164},
  abstract = {Abstract image available at:  http://adsabs.harvard.edu/abs/1961ApJ...134..343K},
  journal = {ApJ}
}

@article{Khan.Hall.ea2018,
  title = {The {{Red}}-Giant {{Branch Bump Revisited}}: {{Constraints}} on {{Envelope Overshooting}} in a {{Wide Range}} of {{Masses}} and {{Metallicities}}},
  shorttitle = {The {{Red}}-Giant {{Branch Bump Revisited}}},
  author = {Khan, Saniya and Hall, Oliver J. and Miglio, Andrea and Davies, Guy R. and Mosser, Beno{\^i}t and Girardi, L{\'e}o and Montalb{\'a}n, Josefina},
  year = {2018},
  month = jun,
  volume = {859},
  pages = {156},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/aabf90},
  abstract = {The red-giant branch bump provides valuable information for the  investigation of the internal structure of low-mass stars. Because current models are unable to accurately predict the occurrence and efficiency of mixing processes beyond convective boundaries, one can use the luminosity of the bump\textemdash a diagnostic of the maximum extension of the convective envelope during the first-dredge up\textemdash as a calibrator for such processes. By combining asteroseismic and spectroscopic constraints, we expand the analysis of the bump to masses and metallicities beyond those previously accessible using globular clusters. Our data set comprises nearly 3000 red-giant stars observed by Kepler and with APOGEE spectra. Using statistical mixture models, we are able to detect the bump in the average seismic parameters {$\nu$} max and {$<$} \{\{{$\Delta$} \}\}{$\nu$} {$>$} , and show that its observed position reveals general trends with mass and metallicity in line with expectations from models. Moreover, our analysis indicates that standard stellar models underestimate the depth of efficiently mixed envelopes. The inclusion of significant overshooting from the base of the convective envelope, with an efficiency that increases with decreasing metallicity, allows us to reproduce the observed location of the bump. Interestingly, this trend was also reported in previous studies of globular clusters.},
  journal = {ApJ},
  keywords = {mass function,stars: evolution,stars: interiors,stars: low-mass,stars: luminosity function}
}

@article{Kiefer.Schad.ea2017,
  title = {Stellar Magnetic Activity and Variability of Oscillation Parameters: {{An}} Investigation of 24 Solar-like Stars Observed by {{Kepler}}},
  shorttitle = {Stellar Magnetic Activity and Variability of Oscillation Parameters},
  author = {Kiefer, Ren{\'e} and Schad, Ariane and Davies, Guy and Roth, Markus},
  year = {2017},
  month = feb,
  volume = {598},
  pages = {A77},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201628469},
  abstract = {Context. The Sun and solar-like stars undergo activity cycles for which  the underlying mechanisms are not well understood. The oscillations of the Sun are known to vary with its activity cycle and these changes provide diagnostics on the conditions below the photosphere. Kepler has detected solar-like oscillations in hundreds of stars but as of yet, no widespread detection of signatures of magnetic activity cycles in the oscillation parameters of these stars have been reported. Aims: We analysed the photometric short cadence Kepler time series of a set of 24 solar-like stars, which were observed for at least 960 d each, with the aim to find signatures of stellar magnetic activity in the oscillation parameters. Methods: We analyse the temporal evolution of oscillation parameters by measuring mode frequency shifts, changes in the height of the p-mode envelope, as well as granulation timescales. Results: For 23 of the 24 investigated stars, we find significant frequency shifts in time. We present evidence for magnetic activity in six of these stars. We find that the amplitude of the frequency shifts decreases with stellar age and rotation period. For KIC 8006161 (the most prominent example), we find that frequency shifts are smallest for the lowest and largest for the highest p-mode frequencies, as they are for the Sun. Conclusions: These findings show that magnetic activity can be routinely observed in the oscillation parameters for solar-like stars, which opens up the possibility of placing the solar activity cycle in the context of other stars by asteroseismology.},
  journal = {A\&A},
  keywords = {asteroseismology,methods: data analysis,stars: activity,stars: magnetic field,stars: oscillations,stars: solar-type}
}

@article{Kinemuchi.Barclay.ea2012,
  title = {Demystifying {{Kepler Data}}: {{A Primer}} for {{Systematic Artifact Mitigation}}},
  shorttitle = {Demystifying {{Kepler Data}}},
  author = {Kinemuchi, K. and Barclay, T. and Fanelli, M. and Pepper, J. and Still, M. and Howell, Steve B.},
  year = {2012},
  month = sep,
  volume = {124},
  pages = {963},
  issn = {0004-6280},
  doi = {10.1086/667603},
  abstract = {The Kepler spacecraft has collected data of high photometric precision and cadence almost continuously since operations began on 2009 May 2. Primarily designed to detect planetary transits and asteroseismological signals from solar-like stars, Kepler has provided high-quality data for many areas of investigation. Unconditioned simple aperture time-series photometry is, however, affected by systematic structure. Examples of these systematics include differential velocity aberration, thermal gradients across the spacecraft, and pointing variations. While exhibiting some impact on Kepler's primary science, these systematics can critically handicap potentially ground-breaking scientific gains in other astrophysical areas, especially over long timescales greater than 10 days. As the data archive grows to provide light curves for 105 stars of many years in length, Kepler will only fulfill its broad potential for stellar astrophysics if these systematics are understood and mitigated. Post-launch developments in the Kepler archive, data reduction pipeline and open source data analysis software have helped to remove or reduce systematic artifacts. This paper provides a conceptual primer to help users of the Kepler data archive understand and recognize systematic artifacts within light curves and some methods for their removal. Specific examples of artifact mitigation are provided using data available within the archive. Through the methods defined here, the Kepler community will find a road map to maximizing the quality and employment of the Kepler legacy archive.},
  journal = {PASP}
}

@article{Kingma.Ba2014,
  ids = {Kingma.Ba2014a},
  title = {Adam: {{A Method}} for {{Stochastic Optimization}}},
  shorttitle = {Adam},
  author = {Kingma, Diederik P. and Ba, Jimmy},
  year = {2014},
  month = dec,
  abstract = {We introduce Adam, an algorithm for first-order gradient-based optimization of stochastic objective functions, based on adaptive estimates of lower-order moments. The method is straightforward to implement, is computationally efficient, has little memory requirements, is invariant to diagonal rescaling of the gradients, and is well suited for problems that are large in terms of data and/or parameters. The method is also appropriate for non-stationary objectives and problems with very noisy and/or sparse gradients. The hyper-parameters have intuitive interpretations and typically require little tuning. Some connections to related algorithms, on which Adam was inspired, are discussed. We also analyze the theoretical convergence properties of the algorithm and provide a regret bound on the convergence rate that is comparable to the best known results under the online convex optimization framework. Empirical results demonstrate that Adam works well in practice and compares favorably to other stochastic optimization methods. Finally, we discuss AdaMax, a variant of Adam based on the infinity norm.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1412.6980},
  eprint = {1412.6980},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Computer Science - Machine Learning},
  primaryclass = {cs.LG}
}

@article{Kippenhahn.Weigert.ea1967,
  title = {Methods for Calculating Stellar Evolution},
  author = {Kippenhahn, R. and Weigert, A. and Hofmeister, Emmi},
  year = {1967},
  month = jan,
  volume = {7},
  pages = {129--190},
  journal = {Methods Comput. Phys.}
}

@book{Kippenhahn.Weigert.ea2012,
  title = {Stellar Structure and Evolution},
  author = {Kippenhahn, Rudolf and Weigert, Alfred and Weiss, Achim},
  year = {2012}
}

@article{Kipping2021,
  title = {Black {{Swans}} in {{Astronomical Data}}},
  author = {Kipping, David},
  year = {2021},
  month = apr,
  volume = {2104},
  pages = {arXiv:2104.07693},
  abstract = {Astronomy has always been propelled by the discovery of new phenomena lacking precedent, often followed by new theories to explain their existence and properties. In the modern era of large surveys tiling the sky at ever high precision and sampling rates, these serendipitous discoveries look set to continue, with recent examples including Boyajian's Star, Fast Radio Bursts and `Oumuamua. Accordingly, we here look ahead and aim to provide a statistical framework for interpreting such events and providing guidance to future observations, under the basic premise that the phenomenon in question stochastically repeat at some unknown, constant rate, \$\textbackslash lambda\$. Specifically, expressions are derived for 1) the a-posteriori distribution for \$\textbackslash lambda\$, 2) the a-posteriori distribution for the recurrence time, and, 3) the benefit-to-cost ratio of further observations relative to that of the inaugural event. Some rule-of-thumb results for each of these are found to be 1) \$\textbackslash lambda {$<$} \textbackslash\{0.7, 2.3, 4.6\textbackslash\}\textbackslash,t\_1\^\{-1\}\$ to \$\textbackslash\{50, 90, 95\textbackslash\}\textbackslash\%\$ confidence (where \$t\_1=\$ time to obtain the first detection), 2) the recurrence time is \$t\_2 {$<$} \textbackslash\{1, 9, 99\textbackslash\}\textbackslash,t\_1\$ to \$\textbackslash\{50, 90, 95\textbackslash\}\textbackslash\%\$ confidence, with a lack of repetition by time \$t\_2\$ yielding a \$p\$-value of \$1/[1+(t\_2/t\_1)]\$, and, 3) follow-up for \$\textbackslash lesssim 10\textbackslash,t\_1\$ is expected to be scientifically worthwhile under an array of differing assumptions about the object's intrinsic scientific value. We apply these methods to the Breakthrough Listen Candidate 1 signal and tidal disruption events observed by TESS.},
  journal = {arXiv e-prints},
  keywords = {Astrophysics - Instrumentation and Methods for Astrophysics}
}

@article{Kjeldsen.Bedding.ea2005,
  title = {Solar-like {{Oscillations}} in {$\alpha$} {{Centauri B}}},
  author = {Kjeldsen, Hans and Bedding, Timothy R. and Butler, R. Paul and {Christensen-Dalsgaard}, J{\o}rgen and Kiss, Laszlo L. and McCarthy, Chris and Marcy, Geoffrey W. and Tinney, Christopher G. and Wright, Jason T.},
  year = {2005},
  month = dec,
  volume = {635},
  pages = {1281--1290},
  doi = {10.1086/497530},
  abstract = {We have made velocity observations of the star {$\alpha$} Centauri B from two sites, allowing us to identify 37 oscillation modes with l=0-3. Fitting to these modes gives the large and small frequency separations as a function of frequency. The mode lifetime, as measured from the scatter of the oscillation frequencies about a smooth trend, is similar to that in the Sun. Limited observations of the star {$\delta$} Pav show oscillations centered at 2.3 mHz, with peak amplitudes close to solar. We introduce a new method of measuring oscillation amplitudes from heavily smoothed power density spectra, from which we estimated amplitudes for {$\alpha$} Cen {$\alpha$} and B, {$\beta$} Hyi, {$\delta$} Pav, and the Sun. We point out that the oscillation amplitudes may depend on which spectral lines are used for the velocity measurements. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programme 71.D-0618).},
  journal = {ApJ},
  keywords = {stars: individual (δ Pavonis),Stars: Individual: Constellation Name: α Centauri A,Stars: Individual: Constellation Name: α Centauri B,Stars: Individual: Constellation Name: β Hydri,Stars: Oscillations,Sun: Helioseismology}
}

@article{Kjeldsen.Bedding.ea2008,
  title = {Correcting {{Stellar Oscillation Frequencies}} for {{Near}}-{{Surface Effects}}},
  author = {Kjeldsen, Hans and Bedding, Timothy R. and {Christensen-Dalsgaard}, J{\o}rgen},
  year = {2008},
  month = aug,
  volume = {683},
  pages = {L175},
  doi = {10.1086/591667},
  abstract = {In helioseismology, there is a well-known offset between observed and computed oscillation frequencies. This offset is known to arise from improper modeling of the near-surface layers of the Sun, and a similar effect must occur for models of other stars. Such an effect impedes progress in asteroseismology, which involves comparing observed oscillation frequencies with those calculated from theoretical models. Here, we use data for the Sun to derive an empirical correction for the near-surface offset, which we then apply to three other stars ({$\alpha$} Cen A, {$\alpha$} Cen B, and {$\beta$} Hyi). The method appears to give good results, in particular providing an accurate estimate of the mean density of each star.},
  journal = {Astrophys. J. Lett.},
  keywords = {stars: individual: β Hyi α Cen A α Cen B,stars: oscillations,Sun: helioseismology}
}

@article{Kjeldsen.Bedding1995,
  title = {Amplitudes of Stellar Oscillations: The Implications for Asteroseismology.},
  shorttitle = {Amplitudes of Stellar Oscillations},
  author = {Kjeldsen, H. and Bedding, T. R.},
  year = {1995},
  month = jan,
  volume = {293},
  pages = {87--106},
  issn = {0004-6361},
  abstract = {There are no good predictions for the amplitudes expected from solar-like oscillations in other stars. In the absence of a definitive model for convection, which is thought to be the mechanism that excites these oscillations, the amplitudes for both velocity and luminosity measurements must be estimated by scaling from the Sun. In the case of luminosity measurements, even this is difficult because of disagreement over the solar amplitude. This last point has lead us to investigate whether the luminosity amplitude of oscillations {$\delta$}L/L can be derived from the velocity amplitude (v\_osc\_). Using linear theory and observational data, we show that p-mode oscillations in a large sample of pulsating stars satisfy ({$\delta$}L/L)\_bol\_\{prop.to\} v\_osc\_/T\_eff\_. Using this relationship, together with the best estimate of v\_osc\_,sun\_=(23.4+/-1.4)cm/s, we estimate the luminosity amplitude of solar oscillations at 550nm to be {$\delta$}L/L=(4.7+/-0.3)ppm. Next we discuss how to scale the amplitude of solar-like (i.e., convectively-powered) oscillations from the Sun to other stars. The only predictions come from model calculations by Christensen-Dalsgaard \& Frandsen (1983, Sol. Phys. 82, 469). However, their grid of stellar models is not dense enough to allow amplitude predictions for an arbitrary star. Nevertheless, although convective theory is complicated, we might expect that the general properties of convection - including oscillation amplitudes - should change smoothly through the colour-magnitude diagram. Indeed, we find that the velocity amplitudes predicted by the model calculations are well fitted by the relation v\_osc\_\{prop.to\}L/M. These two relations allow us to predict both the velocity and luminosity amplitudes of solar-like oscillations in any given star. We compare these predictions with published observations and evaluate claims for detections that have appeared in the literature. We argue that there is not yet good evidence for solar-like oscillations in any star except the Sun. For solar-type stars (e.g., {$\alpha$} Cen A and {$\beta$} Hyi), observations have not yet reached sufficient sensitivity to detect the amplitudes we predict. For some F-type stars, namely Procyon and several members of M67, detection sensitivities 30-40\% below the predicted amplitudes have been achieved. We conclude that these stars must oscillate with amplitudes less than has generally been assumed.},
  journal = {A\&A},
  keywords = {{DELTA} SCT,CEPHEIDS,STARS: INDIVIDUAL: {ALPHA} CEN,STARS: INDIVIDUAL: PROCYON,STARS: OSCILLATIONS,SUN: OSCILLATIONS}
}

@article{Korn.Grundahl.ea2007,
  title = {Atomic {{Diffusion}} and {{Mixing}} in {{Old Stars}}. {{I}}. {{Very Large Telescope FLAMES}}-{{UVES Observations}} of {{Stars}} in {{NGC}} 6397},
  author = {Korn, A. J. and Grundahl, F. and Richard, O. and Mashonkina, L. and Barklem, P. S. and Collet, R. and Gustafsson, B. and Piskunov, N.},
  year = {2007},
  month = dec,
  volume = {671},
  pages = {402--419},
  doi = {10.1086/523098},
  abstract = {We present a homogeneous photometric and spectroscopic analysis of 18  stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H]\textasciitilde -2), from the main-sequence turnoff point to red giants below the bump. The spectroscopic stellar parameters, in particular stellar parameter differences between groups of stars, are in good agreement with broadband and Str\"omgren photometry calibrated on the infrared flux method. The spectroscopic abundance analysis reveals, for the first time, systematic trends of iron abundance with evolutionary stage. Iron is found to be 30\% less abundant in the turnoff point stars than in the red giants. An abundance difference in lithium is seen between the turnoff point and warm subgiant stars. The impact of potential systematic errors on these abundance trends (stellar parameters, the hydrostatic and LTE approximations) is quantitatively evaluated and found not to alter our conclusions significantly. Trends for various elements (Li, Mg, Ca, Ti, and Fe) are compared with stellar structure models including the effects of atomic diffusion and radiative acceleration. Such models are found to describe the observed element-specific trends well, if extra (turbulent) mixing just below the convection zone is introduced. It is concluded that atomic diffusion and turbulent mixing are largely responsible for the subprimordial stellar lithium abundances of warm halo stars. Other consequences of atomic diffusion in old metal-poor stars are also discussed. Based on observations carried out at the European Southern Observatory (ESO), Paranal, Chile, under program ID 075.D-0125(A).},
  journal = {ApJ},
  keywords = {Diffusion,Galaxy: Globular Clusters: Individual: NGC Number: NGC 6397,Stars: Abundances,Stars: Atmospheres,Stars: Evolution,Stars: Fundamental Parameters,Stars: Interiors,Stars: Population II}
}

@article{Kuszlewicz.Chaplin.ea2019,
  title = {Bayesian Hierarchical Inference of Asteroseismic Inclination Angles},
  author = {Kuszlewicz, James S. and Chaplin, William J. and North, Thomas S. H. and Farr, Will M. and Bell, Keaton J. and Davies, Guy R. and Campante, Tiago L. and Hekker, Saskia},
  year = {2019},
  month = sep,
  volume = {488},
  pages = {572--589},
  issn = {0035-8711},
  doi = {10.1093/mnras/stz1689},
  abstract = {The stellar inclination angle - the angle between the rotation axis of a star and our line of sight - provides valuable information in many different areas, from the characterization of the geometry of exoplanetary and eclipsing binary systems to the formation and evolution of those systems. We propose a method based on asteroseismology and a Bayesian hierarchical scheme for extracting the inclination angle of a single star. This hierarchical method therefore provides a means to both accurately and robustly extract inclination angles from red giant stars. We successfully apply this technique to an artificial data set with an underlying isotropic inclination angle distribution to verify the method. We also apply this technique to 123 red giant stars observed with Kepler. We also show the need for a selection function to account for possible population-level biases, which are not present in individual star-by-star cases, in order to extend the hierarchical method towards inferring underlying population inclination angle distributions.},
  journal = {MNRAS},
  keywords = {asteroseismology,methods: data analysis,methods: statistical}
}

@article{Lastname2020,
  title = {Test},
  author = {Lastname, Firstname},
  year = {2020},
  journal = {Test J.}
}

@article{Lebreton.Goupil.ea2014,
  title = {How Accurate Are Stellar Ages Based on Stellar Models?: {{I}}. {{The}} Impact of Stellar Models Uncertainties},
  shorttitle = {How Accurate Are Stellar Ages Based on Stellar Models?},
  author = {Lebreton, Y. and Goupil, M.J. and Montalb{\'a}n, J.},
  editor = {Lebreton, Y. and {Valls-Gabaud}, D. and Charbonnel, C.},
  year = {2014},
  volume = {65},
  pages = {99--176},
  issn = {1633-4760, 1638-1963},
  doi = {10.1051/eas/1465004},
  abstract = {Among the various methods used to age-date stars, methods based on stellar model predictions are widely used, for nearly all kind of stars in large ranges of masses, chemical compositions and evolutionary stages. The precision and accuracy on the age determination depend on both the precision and number of observational constraints, and on our ability to correctly describe the stellar interior and evolution. The imperfect input physics of stellar models as well as the uncertainties on the initial chemical composition of stars are responsible for uncertainties in the age determination. We present an overview of the calculation of stellar models and discuss the impact on age of their numerous inputs.},
  journal = {EAS Publ. Ser.},
  keywords = {stellar ages,stellar models},
  language = {en}
}

@article{Lebreton.Goupil2014,
  title = {Asteroseismology for "\`a La Carte" Stellar Age-Dating and Weighing. {{Age}} and Mass of the {{CoRoT}} Exoplanet Host {{HD}} 52265},
  author = {Lebreton, Y. and Goupil, M. J.},
  year = {2014},
  month = sep,
  volume = {569},
  pages = {A21},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201423797},
  abstract = {Context. In the context of the space missions CoRoT, Kepler, Gaia, TESS,  and PLATO, precise and accurate stellar ages, masses, and radii are of paramount importance. For instance, they are crucial for constraining scenarii of planetary formation and evolution. Aims: We aim at quantifying how detailed stellar modelling can improve the accuracy and precision on age and mass of individual stars. To that end, we adopt a multifaceted approach where we carefully examine how the number of observational constraints as well as the uncertainties on observations and on model input physics affect the results of age-dating and weighing. Methods: We modelled in detail the exoplanet host-star HD 52265, a main-sequence, solar-like oscillator that CoRoT observed for four months. We considered different sets of observational constraints (Hertzsprung-Russell data, metallicity, various sets of seismic constraints). For each case, we determined the age, mass, and properties of HD 52265 inferred from stellar models, and we quantified the impact of the model input physics and free parameters. We also compared model ages with ages derived by empirical methods or Hertzsprung-Russell diagram inversion. Results: For our case study HD 52265, our seismic analysis provides an age A = 2.10-2.54 Gyr, a mass M = 1.14-1.32 M{$\odot$}, and a radius R = 1.30-1.34 R{$\odot$}, which corresponds to age, mass, and radius uncertainties of \textasciitilde 10, \textasciitilde 7, and \textasciitilde 1.5 per cent, respectively. These uncertainties account for observational errors and current state-of-the-art stellar model uncertainties. Our seismic study also provides constraints on surface convection properties through the mixing-length, which we find to be 12-15 per cent lower than the solar value. On the other hand, because of helium-mass degeneracy, the initial helium abundance is determined modulo the mass value. Finally, we evaluate the seismic mass of the exoplanet to be Mpsini = 1.17-1.26 MJupiter, much more precise than what can be derived by Hertzsprung-Russell diagram inversion. Conclusions: We demonstrate that asteroseismology allows us to substantially improve the age accuracy that can be achieved with other methods. We emphasize that the knowledge of the mean properties of stellar oscillations - such as the large frequency separation - is not enough to derive accurate ages. We need precise individual frequencies to narrow the age scatter that is a result of the model input physics uncertainties. Further progress is required to better constrain the physics at work in stars and the stars helium content. Our results emphasize the importance of precise classical stellar parameters and oscillation frequencies such as will be obtained by the Gaia and PLATO missions. Tables 4, 5, and A.2-A.5 are also available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/569/A21Appendices are available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {asteroseismology,planets and satellites: fundamental parameters,stars: evolution,stars: fundamental parameters,stars: individual: HD 52265,stars: interiors}
}

@article{Leistedt.Hogg2017,
  title = {Hierarchical {{Probabilistic Inference}} of the {{Color}}-{{Magnitude Diagram}} and {{Shrinkage}} of {{Stellar Distance Uncertainties}}},
  author = {Leistedt, Boris and Hogg, David W.},
  year = {2017},
  month = dec,
  volume = {154},
  pages = {222},
  issn = {0004-6256},
  doi = {10.3847/1538-3881/aa91d5},
  abstract = {We present a hierarchical probabilistic model for improving geometric  stellar distance estimates using color-magnitude information. This is achieved with a data-driven model of the color-magnitude diagram, not relying on stellar models but instead on the relative abundances of stars in color-magnitude cells, which are inferred from very noisy magnitudes and parallaxes. While the resulting noise-deconvolved color-magnitude diagram can be useful for a range of applications, we focus on deriving improved stellar distance estimates relying on both parallax and photometric information. We demonstrate the efficiency of this approach on the 1.4 million stars of the Gaia TGAS sample that also have AAVSO Photometric All Sky Survey magnitudes. Our hierarchical model has 4 million parameters in total, most of which are marginalized out numerically or analytically. We find that distance estimates are significantly improved for the noisiest parallaxes and densest regions of the color-magnitude diagram. In particular, the average distance signal-to-noise ratio (S/N) and uncertainty improve by 19\% and 36\%, respectively, with 8\% of the objects improving in S/N by a factor greater than 2. This computationally efficient approach fully accounts for both parallax and photometric noise and is a first step toward a full hierarchical probabilistic model of the Gaia data.},
  journal = {AJ},
  keywords = {Hertzsprung-Russell and C-M diagrams,methods: statistical,stars: distances}
}

@article{Li.Bedding.ea2018,
  title = {Modelling {{Kepler}} Red Giants in Eclipsing Binaries: Calibrating the Mixing-Length Parameter with Asteroseismology},
  shorttitle = {Modelling {{Kepler}} Red Giants in Eclipsing Binaries},
  author = {Li, Tanda and Bedding, Timothy R. and Huber, Daniel and Ball, Warrick H. and Stello, Dennis and Murphy, Simon J. and {Bland-Hawthorn}, Joss},
  year = {2018},
  month = mar,
  volume = {475},
  pages = {981--998},
  doi = {10.1093/mnras/stx3079},
  abstract = {Stellar models rely on a number of free parameters. High-quality  observations of eclipsing binary stars observed by Kepler offer a great opportunity to calibrate model parameters for evolved stars. Our study focuses on six Kepler red giants with the goal of calibrating the mixing-length parameter of convection as well as the asteroseismic surface term in models. We introduce a new method to improve the identification of oscillation modes that exploits theoretical frequencies to guide the mode identification (`peak-bagging') stage of the data analysis. Our results indicate that the convective mixing-length parameter ({$\alpha$}) is {$\approx$}14 per cent larger for red giants than for the Sun, in agreement with recent results from modelling the APOGEE stars. We found that the asteroseismic surface term (i.e. the frequency offset between the observed and predicted modes) correlates with stellar parameters (Teff, log g) and the mixing-length parameter. This frequency offset generally decreases as giants evolve. The two coefficients a-1 and a3 for the inverse and cubic terms that have been used to describe the surface term correction are found to correlate linearly. The effect of the surface term is also seen in the p-g mixed modes; however, established methods for correcting the effect are not able to properly correct the g-dominated modes in late evolved stars.},
  journal = {MNRAS},
  keywords = {stars: evolution,stars: oscillations}
}

@article{Licquia.Newman2015,
  title = {Improved {{Estimates}} of the {{Milky Way}}'s {{Stellar Mass}} and {{Star Formation Rate}} from {{Hierarchical Bayesian Meta}}-{{Analysis}}},
  author = {Licquia, Timothy C. and Newman, Jeffrey A.},
  year = {2015},
  month = jun,
  volume = {806},
  pages = {96},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/806/1/96},
  abstract = {We present improved estimates of several global properties of the Milky  Way, including its current star formation rate (SFR), the stellar mass contained in its disk and bulge+bar components, as well as its total stellar mass. We do so by combining previous measurements from the literature using a hierarchical Bayesian (HB) statistical method that allows us to account for the possibility that any value may be incorrect or have underestimated errors. We show that this method is robust to a wide variety of assumptions about the nature of problems in individual measurements or error estimates. Ultimately, our analysis yields an SFR for the Galaxy of \{\{\textbackslash dot\{M\}\}\textbackslash star \}=1.65+/- 0.19 \{\{M\}{$\odot$} \} y\{\{r\}-1\}, assuming a Kroupa initial mass function (IMF). By combining HB methods with Monte Carlo simulations that incorporate the latest estimates of the Galactocentric radius of the Sun, R0, the exponential scale length of the disk, Ld, and the local surface density of stellar mass, \{\{{$\Sigma\rbrace\backslash$}star \}(\{\{R\}0\}), we show that the mass of the Galactic bulge+bar is M\textbackslash star B=0.91+/- 0.07\texttimes{} \{\{10\}10\} \{\{M\}{$\odot$} \}, the disk mass is M\textbackslash star D=5.17+/- 1.11\texttimes{} \{\{10\}10\} \{\{M\}{$\odot$} \}, and their combination yields a total stellar mass of \{\{M\}\textbackslash star \}=6.08+/- 1.14\texttimes{} \{\{10\}10\} \{\{M\}{$\odot$} \} (assuming a Kroupa IMF and an exponential disk profile). This analysis is based upon a new compilation of literature bulge mass estimates, normalized to common assumptions about the stellar IMF and Galactic disk properties, presented herein. We additionally find a bulge-to-total mass ratio for the Milky Way of B/T=0.150-0.019+0.028 and a specific SFR of \{\{\textbackslash dot\{M\}\}\textbackslash star \}/\{\{M\}\textbackslash star \}=2.71+/- 0.59\texttimes{} \{\{10\}-11\} yr-1.\vphantom\}},
  journal = {ApJ},
  keywords = {Galaxy: bulge,Galaxy: disk,Galaxy: fundamental parameters,Galaxy: stellar content,methods: statistical,stars: formation}
}

@article{LightkurveCollaboration.Cardoso.ea2018,
  title = {Lightkurve: {{Kepler}} and {{TESS}} Time Series Analysis in {{Python}}},
  shorttitle = {Lightkurve},
  author = {{Lightkurve Collaboration} and Cardoso, Jos{\'e} Vin{\'i}cius de Miranda and Hedges, Christina and {Gully-Santiago}, Michael and Saunders, Nicholas and Cody, Ann Marie and Barclay, Thomas and Hall, Oliver and Sagear, Sheila and Turtelboom, Emma and Zhang, Johnny and Tzanidakis, Andy and Mighell, Ken and Coughlin, Jeff and Bell, Keaton and {Berta-Thompson}, Zach and Williams, Peter and Dotson, Jessie and Barentsen, Geert},
  year = {2018},
  month = dec,
  pages = {ascl:1812.013},
  abstract = {Lightkurve analyzes astronomical flux time series data, in particular the pixels and light curves obtained by NASA's Kepler, K2, and TESS exoplanet missions. This community-developed Python package is designed to be user friendly to lower the barrier for students, astronomers, and citizen scientists interested in analyzing data from these missions. Lightkurve provides easy tools to download, inspect, and analyze time series data and its documentation is supported by a large syllabus of tutorials.},
  journal = {Astrophys. Source Code Libr.},
  keywords = {Kepler,NASA,python,Software,TESS}
}

@article{Lindegren.Hernandez.ea2018,
  title = {Gaia {{Data Release}} 2. {{The}} Astrometric Solution},
  author = {Lindegren, L. and Hern{\'a}ndez, J. and Bombrun, A. and Klioner, S. and Bastian, U. and {Ramos-Lerate}, M. and {de Torres}, A. and Steidelm{\"u}ller, H. and Stephenson, C. and Hobbs, D. and Lammers, U. and Biermann, M. and Geyer, R. and Hilger, T. and Michalik, D. and Stampa, U. and McMillan, P. J. and Casta{\~n}eda, J. and Clotet, M. and Comoretto, G. and Davidson, M. and Fabricius, C. and Gracia, G. and Hambly, N. C. and Hutton, A. and Mora, A. and Portell, J. and {van Leeuwen}, F. and Abbas, U. and Abreu, A. and Altmann, M. and Andrei, A. and Anglada, E. and {Balaguer-N{\'u}{\~n}ez}, L. and Barache, C. and Becciani, U. and Bertone, S. and Bianchi, L. and Bouquillon, S. and Bourda, G. and Br{\"u}semeister, T. and Bucciarelli, B. and Busonero, D. and Buzzi, R. and Cancelliere, R. and Carlucci, T. and Charlot, P. and Cheek, N. and Crosta, M. and Crowley, C. and {de Bruijne}, J. and {de Felice}, F. and Drimmel, R. and Esquej, P. and Fienga, A. and Fraile, E. and Gai, M. and Garralda, N. and {Gonz{\'a}lez-Vidal}, J. J. and Guerra, R. and Hauser, M. and Hofmann, W. and Holl, B. and Jordan, S. and Lattanzi, M. G. and Lenhardt, H. and Liao, S. and Licata, E. and Lister, T. and L{\"o}ffler, W. and Marchant, J. and {Martin-Fleitas}, J.-M. and Messineo, R. and Mignard, F. and Morbidelli, R. and Poggio, E. and Riva, A. and Rowell, N. and Salguero, E. and Sarasso, M. and Sciacca, E. and Siddiqui, H. and Smart, R. L. and Spagna, A. and Steele, I. and Taris, F. and Torra, J. and {van Elteren}, A. and {van Reeven}, W. and Vecchiato, A.},
  year = {2018},
  month = aug,
  volume = {616},
  pages = {A2},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201832727},
  abstract = {Context. Gaia Data Release 2 (Gaia DR2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by the European Space Agency Gaia satellite during the first 22 months of its operational phase. Aims: We describe the input data, models, and processing used for the astrometric content of Gaia DR2, and the validation of these resultsperformed within the astrometry task. Methods: Some 320 billion centroid positions from the pre-processed astrometric CCD observations were used to estimate the five astrometric parameters (positions, parallaxes, and proper motions) for 1332 million sources, and approximate positions at the reference epoch J2015.5 for an additional 361 million mostly faint sources. These data were calculated in two steps. First, the satellite attitude and the astrometric calibration parameters of the CCDs were obtained in an astrometric global iterative solution for 16 million selected sources, using about 1\% of the input data. This primary solution was tied to the extragalactic International Celestial Reference System (ICRS) by means of quasars. The resulting attitude and calibration were then used to calculate the astrometric parameters of all the sources. Special validation solutions were used to characterise the random and systematic errors in parallax and proper motion. Results: For the sources with five-parameter astrometric solutions, the median uncertainty in parallax and position at the reference epoch J2015.5 is about 0.04 mas for bright (G {$<$} 14 mag) sources, 0.1 mas at G = 17 mag, and 0.7 masat G = 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr-1, respectively.The optical reference frame defined by Gaia DR2 is aligned with ICRS and is non-rotating with respect to the quasars to within 0.15 mas yr-1. From the quasars and validation solutions we estimate that systematics in the parallaxes depending on position, magnitude, and colour are generally below 0.1 mas, but the parallaxes are on the whole too small by about 0.03 mas. Significant spatial correlations of up to 0.04 mas in parallax and 0.07 mas yr-1 in proper motion are seen on small ({$<$} 1 deg) and intermediate (20 deg) angular scales. Important statistics and information for the users of the Gaia DR2 astrometry are given in the appendices.},
  journal = {A\&A},
  keywords = {astrometry,methods: data analysis,parallaxes,proper motions,reference systems,space vehicles: instruments}
}

@article{Lomb1976,
  title = {Least-Squares Frequency Analysis of Unequally Spaced Data},
  author = {Lomb, N. R.},
  year = {1976},
  month = feb,
  volume = {39},
  pages = {447--462},
  issn = {0004-640X},
  doi = {10.1007/BF00648343},
  abstract = {The statistical properties of least-squares frequency analysis of unequally spaced data are examined. It is shown that, in the least-squares spectrum of gaussian noise, the reduction in the sum of squares at a particular frequency is a chi2-squared variable. The reductions at different frequencies are not independent, as there is a correlation between the height of the spectrum at any two frequencies, f1 and f2, which is equal to the mean height of the spectrum due to a sinusoidal signal of frequency f1, at the frequency f2. These correlations reduce the distortion in the spectrum of a signal affected by noise. Some numerical illustrations of the properties of least-squares frequency spectra are given.},
  journal = {Ap\&SS},
  keywords = {Astronomy,Background Noise,Data Reduction,Least Squares Method,Power Spectra,Sine Waves,Spectrum Analysis,Statistical Analysis,Variable Stars}
}

@article{Ludwig.Freytag.ea1999,
  title = {A Calibration of the Mixing-Length for Solar-Type Stars Based on Hydrodynamical Simulations. {{I}}. {{Methodical}} Aspects and Results for Solar Metallicity},
  author = {Ludwig, Hans-G{\"u}nter and Freytag, Bernd and Steffen, Matthias},
  year = {1999},
  month = jun,
  volume = {346},
  pages = {111--124},
  issn = {0004-6361},
  abstract = {Based on detailed 2D numerical radiation hydrodynamics (RHD)  calculations of time-dependent compressible convection, we have studied the dynamics and thermal structure of the convective surface layers of solar-type stars. The RHD models provide information about the convective efficiency in the superadiabatic region at the top of convective envelopes and predict the asymptotic value of the entropy of the deep, adiabatically stratified layers (Fig. \textbackslash ref\{f:sstarhd\}). This information is translated into an effective mixing-length parameter \textbackslash alphaMLT suitable to construct standard stellar structure models. We validate the approach by a detailed comparison to helioseismic data. The grid of RHD models for solar metallicity comprises 58 simulation runs with a helium abundance of Y=0.28 in the range of effective temperatures 4300pun \{K\}{$<$}=Teff{$<$}= 7100pun \{K\} and gravities 2.54{$<$}=\{log g\}{$<$}= 4.74. We find a moderate, nevertheless significant variation of \textbackslash alphaMLT between about 1.3 for F-dwarfs and 1.75 for K-subgiants with a dominant dependence on Teff (Fig. \textbackslash ref\{f:mlp\}). In the close neighbourhood of the Sun we find a plateau where \textbackslash alphaMLT remains almost constant. The internal accuracy of the calibration of \textbackslash alphaMLT is estimated to be +/- 0.05 with a possible systematic bias towards lower values. An analogous calibration of the convection theory of Canuto \&\textbackslash{} Mazzitelli (1991, 1992; CMT) gives a different temperature dependence but a similar variation of the free parameter (Fig. \textbackslash ref\{f:mlpcm\}). For the first time, values for the gravity-darkening exponent beta are derived independently of mixing-length theory: beta = 0.07... 0.10. We show that our findings are consistent with constraints from stellar stability considerations and provide compact fitting formulae for the calibrations.},
  journal = {A\&A},
  keywords = {CONVECTION,HYDRODYNAMICS,STARS: EVOLUTION,STARS: LATE-TYPE}
}

@article{Lund.SilvaAguirre.ea2017,
  title = {Standing on the {{Shoulders}} of {{Dwarfs}}: The {{Kepler Asteroseismic LEGACY Sample}}. {{I}}. {{Oscillation Mode Parameters}}},
  shorttitle = {Standing on the {{Shoulders}} of {{Dwarfs}}},
  author = {Lund, Mikkel N. and Silva Aguirre, V{\'i}ctor and Davies, Guy R. and Chaplin, William J. and {Christensen-Dalsgaard}, J{\o}rgen and Houdek, G{\"u}nter and White, Timothy R. and Bedding, Timothy R. and Ball, Warrick H. and Huber, Daniel and Antia, H. M. and Lebreton, Yveline and Latham, David W. and Handberg, Rasmus and Verma, Kuldeep and Basu, Sarbani and Casagrande, Luca and Justesen, Anders B. and Kjeldsen, Hans and Mosumgaard, Jakob R.},
  year = {2017},
  month = feb,
  volume = {835},
  pages = {172},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/835/2/172},
  abstract = {The advent of space-based missions like Kepler has revolutionized the  study of solar-type stars, particularly through the measurement and modeling of their resonant modes of oscillation. Here we analyze a sample of 66 Kepler main-sequence stars showing solar-like oscillations as part of the Kepler seismic LEGACY project. We use Kepler short-cadence data, of which each star has at least 12 months, to create frequency-power spectra optimized for asteroseismology. For each star, we identify its modes of oscillation and extract parameters such as frequency, amplitude, and line width using a Bayesian Markov chain Monte Carlo ``peak-bagging'' approach. We report the extracted mode parameters for all 66 stars, as well as derived quantities such as frequency difference ratios, the large and small separations \{\{{$\Delta$} \}\}{$\nu$} and {$\delta$} \{{$\nu$} \}02; the behavior of line widths with frequency and line widths at \{{$\nu$} \}\textbackslash max with \{T\}\{eff\}, for which we derive parametrizations; and behavior of mode visibilities. These average properties can be applied in future peak-bagging exercises to better constrain the parameters of the stellar oscillation spectra. The frequencies and frequency ratios can tightly constrain the fundamental parameters of these solar-type stars, and mode line widths and amplitudes can test models of mode damping and excitation.},
  journal = {ApJ},
  keywords = {asteroseismology,stars: evolution,stars: fundamental parameters,stars: oscillations}
}

@article{Magic.Weiss.ea2015,
  title = {The {{Stagger}}-Grid: {{A}} Grid of {{3D}} Stellar Atmosphere Models. {{III}}. {{The}} Relation to Mixing Length Convection Theory},
  shorttitle = {The {{Stagger}}-Grid},
  author = {Magic, Z. and Weiss, A. and Asplund, M.},
  year = {2015},
  month = jan,
  volume = {573},
  pages = {A89},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201423760},
  abstract = {Aims: We investigate the relation between 1D atmosphere models  that rely on the mixing length theory and models based on full 3D radiative hydrodynamic (RHD) calculations to describe convection in the envelopes of late-type stars. Methods: The adiabatic entropy value of the deep convection zone, sbot, and the entropy jump, {$\Delta$}s, determined from the 3D RHD models, were matched with the mixing length parameter, {$\alpha$}MLT, from 1D hydrostatic atmosphere models with identical microphysics (opacities and equation-of-state). We also derived the mass mixing length parameter, {$\alpha$}m, and the vertical correlation length of the vertical velocity, C[vz,vz], directly from the 3D hydrodynamical simulations of stellar subsurface convection.  Results: The calibrated mixing length parameter for the Sun is {$\alpha$}๏MLT (Sbot) = 1.98. . For different stellar parameters, {$\alpha$}MLT varies systematically in the range of 1.7 - 2.4. In particular, {$\alpha$}MLT decreases towards higher effective temperature, lower surface gravity and higher metallicity. We find equivalent results for {$\alpha$}๏MLT ({$\Delta$}S). In addition, we find a tight correlation between the mixing length parameter and the inverse entropy jump. We derive an analytical expression from the hydrodynamic mean-field equations that motivates the relation to the mass mixing length parameter, {$\alpha$}m, and find that it qualitatively shows a similar variation with stellar parameter (between 1.6 and 2.4) with the solar value of {$\alpha$}๏m = 1.83.. The vertical correlation length scaled with the pressure scale height yields 1.71 for the Sun, but only displays a small systematic variation with stellar parameters, the correlation length slightly increases with Teff.  Conclusions: We derive mixing length parameters for various stellar parameters that can be used to replace a constant value. Within any convective envelope, {$\alpha$}m and related quantities vary strongly. Our results will help to replace a constant {$\alpha$}MLT. Appendices are available in electronic form at http://www.aanda.orgFull Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A89 as well as at http://www.stagger-stars.net},
  journal = {A\&A},
  keywords = {convection,hydrodynamics,mixing length theory,stars: atmospheres,stars: evolution,stars: late-type,stars: solar-type,stellar atmospheres,stellar convection}
}

@article{Majewski.Schiavon.ea2017,
  title = {The {{Apache Point Observatory Galactic Evolution Experiment}} ({{APOGEE}})},
  author = {Majewski, Steven R. and Schiavon, Ricardo P. and Frinchaboy, Peter M. and Allende Prieto, Carlos and Barkhouser, Robert and Bizyaev, Dmitry and Blank, Basil and Brunner, Sophia and Burton, Adam and Carrera, Ricardo and Chojnowski, S. Drew and Cunha, K{\'a}tia and Epstein, Courtney and Fitzgerald, Greg and Garc{\'i}a P{\'e}rez, Ana E. and Hearty, Fred R. and Henderson, Chuck and Holtzman, Jon A. and Johnson, Jennifer A. and Lam, Charles R. and Lawler, James E. and Maseman, Paul and M{\'e}sz{\'a}ros, Szabolcs and Nelson, Matthew and Nguyen, Duy Coung and Nidever, David L. and Pinsonneault, Marc and Shetrone, Matthew and Smee, Stephen and Smith, Verne V. and Stolberg, Todd and Skrutskie, Michael F. and Walker, Eric and Wilson, John C. and Zasowski, Gail and Anders, Friedrich and Basu, Sarbani and Beland, Stephane and Blanton, Michael R. and Bovy, Jo and Brownstein, Joel R. and Carlberg, Joleen and Chaplin, William and Chiappini, Cristina and Eisenstein, Daniel J. and Elsworth, Yvonne and Feuillet, Diane and Fleming, Scott W. and {Galbraith-Frew}, Jessica and Garc{\'i}a, Rafael A. and {Garc{\'i}a-Hern{\'a}ndez}, D. An{\'i}bal and Gillespie, Bruce A. and Girardi, L{\'e}o and Gunn, James E. and Hasselquist, Sten and Hayden, Michael R. and Hekker, Saskia and Ivans, Inese and Kinemuchi, Karen and Klaene, Mark and Mahadevan, Suvrath and Mathur, Savita and Mosser, Beno{\^i}t and Muna, Demitri and Munn, Jeffrey A. and Nichol, Robert C. and O'Connell, Robert W. and Parejko, John K. and Robin, A. C. and {Rocha-Pinto}, Helio and Schultheis, Matthias and Serenelli, Aldo M. and Shane, Neville and Silva Aguirre, Victor and Sobeck, Jennifer S. and Thompson, Benjamin and Troup, Nicholas W. and Weinberg, David H. and Zamora, Olga},
  year = {2017},
  month = sep,
  volume = {154},
  pages = {94},
  doi = {10.3847/1538-3881/aa784d},
  abstract = {The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the Sloan 2.5 m Telescope, APOGEE has collected a half million high-resolution (R {$\sim$} 22,500), high signal-to-noise ratio ({$>$}100), infrared (1.51-1.70 {$\mu$}m) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design\textemdash hardware, field placement, target selection, operations\textemdash and gives an overview of these aspects as well as the data reduction, analysis, and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity, and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12 and later releases, all of the APOGEE data products are publicly available.},
  journal = {AJ},
  keywords = {Galaxy: abundances,Galaxy: evolution,Galaxy: formation,Galaxy: kinematics and dynamics,Galaxy: stellar content,Galaxy: structure}
}

@article{Martinez2015,
  title = {A Robust Determination of {{Milky Way}} Satellite Properties Using Hierarchical Mass Modelling},
  author = {Martinez, Gregory D.},
  year = {2015},
  month = aug,
  volume = {451},
  pages = {2524--2535},
  issn = {0035-8711},
  doi = {10.1093/mnras/stv942},
  abstract = {We introduce a new methodology to robustly determine the mass profile,  as well as the overall distribution, of Local Group satellite galaxies. Specifically, we employ a statistical multilevel modelling technique, Bayesian hierarchical modelling, to simultaneously constrain the properties of individual Local Group Milky Way satellite galaxies and the characteristics of the Milky Way satellite population. We show that this methodology reduces the uncertainty in individual dwarf galaxy mass measurements up to a factor of a few for the faintest galaxies. We find that the distribution of Milky Way satellites inferred by this analysis, with the exception of the apparent lack of high-mass haloes, is consistent with the {$\Lambda$} cold dark matter ({$\Lambda$}CDM) paradigm. In particular, we find that both the measured relationship between the maximum circular velocity and the radius at this velocity, as well as the inferred relationship between the mass within 300 pc and luminosity, match the values predicted by {$\Lambda$}CDM simulations for haloes with maximum circular velocities below 20 km s-1. Perhaps more striking is that this analysis seems to suggest a more cusped `average' halo shape that is shared by these galaxies. While this study reconciles many of the observed properties of the Milky Way satellite distribution with that of {$\Lambda$}CDM simulations, we find that there is still a deficit of satellites with maximum circular velocities of 20-40 km s-1.},
  journal = {MNRAS},
  keywords = {galaxies: dwarf,galaxies: kinematics and dynamics,galaxies: statistics,galaxies: structure,Local Group,methods: statistical}
}

@article{Masters.Luschi2018,
  ids = {Masters.Luschi2018a},
  title = {Revisiting {{Small Batch Training}} for {{Deep Neural Networks}}},
  author = {Masters, Dominic and Luschi, Carlo},
  year = {2018},
  month = apr,
  abstract = {Modern deep neural network training is typically based on mini-batch stochastic gradient optimization. While the use of large mini-batches increases the available computational parallelism, small batch training has been shown to provide improved generalization performance and allows a significantly smaller memory footprint, which might also be exploited to improve machine throughput. In this paper, we review common assumptions on learning rate scaling and training duration, as a basis for an experimental comparison of test performance for different mini-batch sizes. We adopt a learning rate that corresponds to a constant average weight update per gradient calculation (i.e., per unit cost of computation), and point out that this results in a variance of the weight updates that increases linearly with the mini-batch size \$m\$. The collected experimental results for the CIFAR-10, CIFAR-100 and ImageNet datasets show that increasing the mini-batch size progressively reduces the range of learning rates that provide stable convergence and acceptable test performance. On the other hand, small mini-batch sizes provide more up-to-date gradient calculations, which yields more stable and reliable training. The best performance has been consistently obtained for mini-batch sizes between \$m = 2\$ and \$m = 32\$, which contrasts with recent work advocating the use of mini-batch sizes in the thousands.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1804.07612},
  eprint = {1804.07612},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Computer Science - Computer Vision and Pattern Recognition,Computer Science - Machine Learning,Statistics - Machine Learning},
  primaryclass = {cs.LG}
}

@article{Mazumdar.Monteiro.ea2014,
  title = {Measurement of {{Acoustic Glitches}} in {{Solar}}-Type {{Stars}} from {{Oscillation Frequencies Observed}} by {{Kepler}}},
  author = {Mazumdar, A. and Monteiro, M. J. P. F. G. and Ballot, J. and Antia, H. M. and Basu, S. and Houdek, G. and Mathur, S. and Cunha, M. S. and Silva Aguirre, V. and Garc{\'i}a, R. A. and Salabert, D. and Verner, G. A. and {Christensen-Dalsgaard}, J. and Metcalfe, T. S. and Sanderfer, D. T. and Seader, S. E. and Smith, J. C. and Chaplin, W. J.},
  year = {2014},
  month = feb,
  volume = {782},
  pages = {18},
  doi = {10.1088/0004-637X/782/1/18},
  abstract = {For the very best and brightest asteroseismic solar-type targets  observed by Kepler, the frequency precision is sufficient to determine the acoustic depths of the surface convective layer and the helium ionization zone. Such sharp features inside the acoustic cavity of the star, which we call acoustic glitches, create small oscillatory deviations from the uniform spacing of frequencies in a sequence of oscillation modes with the same spherical harmonic degree. We use these oscillatory signals to determine the acoustic locations of such features in 19 solar-type stars observed by the Kepler mission. Four independent groups of researchers utilized the oscillation frequencies themselves, the second differences of the frequencies and the ratio of the small and large separation to locate the base of the convection zone and the second helium ionization zone. Despite the significantly different methods of analysis, good agreement was found between the results of these four groups, barring a few cases. These results also agree reasonably well with the locations of these layers in representative models of the stars. These results firmly establish the presence of the oscillatory signals in the asteroseismic data and the viability of several techniques to determine the location of acoustic glitches inside stars.},
  journal = {ApJ},
  keywords = {stars: interiors,stars: oscillations}
}

@article{McKeever.Basu.ea2019,
  title = {The {{Helium Abundance}} of {{NGC}} 6791 from {{Modeling}} of {{Stellar Oscillations}}},
  author = {McKeever, Jean M. and Basu, Sarbani and Corsaro, Enrico},
  year = {2019},
  month = apr,
  volume = {874},
  pages = {180},
  doi = {10.3847/1538-4357/ab0c04},
  abstract = {The helium abundance of stars is a strong driver of evolutionary timescales; however, it is difficult to measure in cool stars. We conduct an asteroseismic analysis of NGC 6791, an old, metal-rich open cluster that previous studies have indicated also has a high helium abundance. The cluster was observed by Kepler and has unprecedented light curves for many of the red giant branch stars in the cluster. Previous asteroseismic studies with Kepler data have constrained the age through grid-based modeling of the global asteroseismic parameters (\{\{{$\Delta$} \}\}{$\nu$} and \{{$\nu$} \}\textbackslash max ). However, with the precision of Kepler data, it is possible to do detailed asteroseismology of individual mode frequencies to better constrain the stellar parameters, something that has not been done for these cluster stars as yet. In this work, we use the observed mode frequencies in 27 hydrogen shell burning red giants to better constrain initial helium abundance (Y 0) and age of the cluster. The distributions of helium abundance and age for each individual red giant are combined to create a final probability distribution for age and helium abundance of the entire cluster. We find a helium abundance of Y 0 = 0.297 {$\pm$} 0.003 and a corresponding age of 8.2 {$\pm$} 0.3 Gyr.},
  journal = {ApJ},
  keywords = {open clusters and associations: general,open clusters and associations: individual: NGC 6791,stars: oscillations}
}

@article{Miglio.Montalban.ea2010,
  title = {Evidence for a Sharp Structure Variation inside a Red-Giant Star},
  author = {Miglio, A. and Montalb{\'a}n, J. and Carrier, F. and De Ridder, J. and Mosser, B. and Eggenberger, P. and Scuflaire, R. and Ventura, P. and D'Antona, F. and Noels, A. and Baglin, A.},
  year = {2010},
  month = sep,
  volume = {520},
  pages = {L6},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201015442},
  abstract = {Context. The availability of precisely determined frequencies of radial and non-radial oscillation modes in red giants is finally paving the way for detailed studies of the internal structure of these stars. Aims: We look for the seismic signature of regions of sharp structure variation in the internal structure of the CoRoT target HR 7349. Methods: We analyse the frequency dependence of the large frequency separation and second frequency differences, as well as the behaviour of the large frequency separation obtained with the envelope auto-correlation function. Results: We find evidence for a periodic component in the oscillation frequencies, i.e. the seismic signature of a sharp structure variation in HR 7349. In a comparison with stellar models we interpret this feature as caused by a local depression of the sound speed that occurs in the helium second-ionization region. Using solely seismic constraints this allows us to estimate the mass (M = 1.2-0.4+0.6 M\_{$\odot$}) and radius (R = 12.2-1.8+2.1 R\_{$\odot$}) of HR 7349, which agrees with the location of the star in an HR diagram.},
  journal = {A\&A},
  keywords = {asteroseismology,stars: fundamental parameters,stars: individual: HR 7349,stars: interiors,stars: oscillations}
}

@article{Moedas.Nsamba.ea2020,
  title = {Asteroseismic Stellar Modelling: Systematics from the Treatment of the Initial Helium Abundance},
  shorttitle = {Asteroseismic Stellar Modelling},
  author = {Moedas, Nuno and Nsamba, Benard and Clara, Miguel T.},
  year = {2020},
  month = jul,
  abstract = {Despite the fact that the initial helium abundance is an essential  ingredient in modelling solar-type stars, its abundance in these stars remains a poorly constrained observational property. This is because the effective temperature in these stars is not high enough to allow helium ionization, not allowing any conclusions on its abundance when spectroscopic techniques are employed. To this end, stellar modellers resort to estimating the initial helium abundance via a semi-empirical helium-to-heavy element ratio, anchored to the the standard Big Bang nucleosynthesis value. Depending on the choice of solar composition used in stellar model computations, the helium-to-heavy element ratio, (\$\textbackslash Delta Y/\textbackslash Delta Z\$) is found to vary between 1 and 3. In this study, we use the Kepler "LEGACY" stellar sample, for which precise seismic data is available, and explore the systematic uncertainties on the inferred stellar parameters (radius, mass, and age) arising from adopting different values of \$\textbackslash Delta Y/\textbackslash Delta Z\$, specifically, 1.4 and 2.0. The stellar grid constructed with a higher \$\textbackslash Delta Y / \textbackslash Delta Z\$ value yields lower radius and mass estimates. We found systematic uncertainties of 1.1 per cent, 2.6 per cent, and 13.1 per cent on radius, mass, and ages, respectively.},
  journal = {arXiv e-prints},
  keywords = {Astrophysics - Solar and Stellar Astrophysics}
}

@article{Monteiro.Christensen-Dalsgaard.ea1994,
  title = {Seismic Study of Overshoot at the Base of the Solar Convective Envelope},
  author = {Monteiro, M. J. P. F. G. and {Christensen-Dalsgaard}, J. and Thompson, M. J.},
  year = {1994},
  month = mar,
  volume = {283},
  pages = {247--262},
  issn = {0004-6361},
  abstract = {Sharp transitions in the internal stratification of a star give rise to a characteristic signature in normal-mode frequencies. In particular, if in the Sun such a feature were located well inside the acoustic cavity of many solar p modes, it would give rise to a signal that was a periodic function of the frequency of the modes. We use this signature to detect the base of the solar convection zone and to investigate the existence of convective overshoot into the radiative interior. Two methods are considered. The 'absolute' method obtains the residuals in the frequencies after making a smooth fit in mode order n, and then uses an asymptotic description of the eigenfunctions to make a fit to the residuals. The 'differential' method makes an asymptotic fit to the differences between solar frequencies and the frequencies of a theoretical model. Various theoretical models of overshoot at the base of the convection zone predict the existence of a rather abrupt transition to subadiabatic stratification at the base of the overshoot region. We find no strong evidence for the existence of an overshoot region of this kind. Indeed if the overshoot consists of an essentially adiabatic extension of the convection zone followed by an abrupt transition to radiative stratification then we may (at the 95\% confidence level) put an upper limit of 0.07 local pressure scale heights on the extent of the overshoot layer.},
  journal = {Astronomy and Astrophysics},
  keywords = {Helioseismology,P Waves,Solar Convection (Astronomy),Solar Oscillations,Solar Physics,Stellar Envelopes,Stellar Models,Stellar Structure,Variational Principles}
}

@article{Monteiro.Christensen-Dalsgaard.ea2000,
  title = {Seismic Study of Stellar Convective Regions: The Base of the Convective Envelope in Low-Mass Stars},
  shorttitle = {Seismic Study of Stellar Convective Regions},
  author = {Monteiro, M{\'a}rio J. P. F. G. and {Christensen-Dalsgaard}, J{\o}rgen and Thompson, Michael J.},
  year = {2000},
  month = jul,
  volume = {316},
  pages = {165--172},
  doi = {10.1046/j.1365-8711.2000.03471.x},
  abstract = {The possibility of observing solar-type oscillations on other stars is  of great relevance to investigating the uncertain aspects of the internal structure of stars. One of these aspects is the convective overshoot that takes place at the borders of the envelopes of stars of mass similar to, or lower than, the Sun. It affects the temperature stratification, mixing, rotation and magnetic-field generation. Asteroseismology can provide an observational test for the studies of the structure of such overshoot regions. The seismic study of the transition in the Sun, located at the base of the convection zone, has been successful in determining the characteristics of this layer in the Sun. In this work we consider the extension of the analysis to other solar-type stars (of mass between 0.85 and 1.2Msolar) in order to establish a method for determining the characteristics of their convective envelopes. In particular, we hope to be able to establish seismologically that a star does indeed possess a convective envelope, to measure the size of the convective region and also to constrain the properties of an overshoot layer at the bottom of the envelope. The limitations in terms of observational uncertainties and stellar characteristics, and the detectability of an overshoot layer, are discussed.},
  journal = {MNRAS},
  keywords = {CONVECTION,STARS: EVOLUTION,STARS: INTERIORS,STARS: OSCILLATIONS}
}

@article{Monteiro.Thompson1998,
  title = {On the Seismic Signature of the {{HeII}} Ionization Zone in Stellar Envelopes},
  author = {Monteiro, M. J. P. F. G. and Thompson, M. J.},
  year = {1998},
  volume = {185},
  pages = {317},
  abstract = {The method developed for the seismic measurement of convective overshoot (Christensen-Dalsgaard et al 1995, MNRAS 276, 283) can be extended in order to study the layer where the second ionization of helium takes place in a star's envelope. Because this zone is confined to a very thin region the effects on the structure can be treated as the result of a localized perturbation to an otherwise smooth behaviour. Therefore, we may hope to be able to use the characteristic periodic signal in the frequencies of oscillation, arising from such a localized perturbation, to determine important aspects of this region. In this poster we present the theoretical analysis of such a signal showing how its different characteristics are associated with the different physical aspects contributing for the zone of the second ionization of helium. Some of these aspects we consider are the envelope helium abundance and the properties of the equation of state (EOS). In this way we attempt to establish how such a characteristic signal can be used to study seismologically the Sun and other stars.}
}

@article{Morel.Lebreton2008,
  title = {{{CESAM}}: A Free Code for Stellar Evolution Calculations},
  shorttitle = {{{CESAM}}},
  author = {Morel, P. and Lebreton, Y.},
  year = {2008},
  month = aug,
  volume = {316},
  pages = {61--73},
  doi = {10.1007/s10509-007-9663-9},
  abstract = {The cesam code is a consistent set of programs and routines which perform calculations of 1D quasi-hydrostatic stellar evolution including microscopic diffusion of chemical species and diffusion of angular momentum. The solution of the quasi-static equilibrium is performed by a collocation method based on piecewise polynomials approximations projected on a B-spline basis; that allows stable and robust calculations, and the exact restitution of the solution, not only at grid points, even for the discontinuous variables. Other advantages are the monitoring by only one parameter of the accuracy and its improvement by super-convergence. An automatic mesh refinement has been designed for adjusting the localisations of grid points according to the changes of unknowns. For standard models, the evolution of the chemical composition is solved by stiffly stable schemes of orders up to four; in the convection zones mixing and evolution of chemical are simultaneous. The solution of the diffusion equation employs the Galerkin finite elements scheme; the mixing of chemicals is then performed by a strong turbulent diffusion. A precise restoration of the atmosphere is allowed for.},
  journal = {Ap\&SS}
}

@article{Morton.Winn2014,
  title = {Obliquities of {{Kepler Stars}}: {{Comparison}} of {{Single}}- and {{Multiple}}-Transit {{Systems}}},
  shorttitle = {Obliquities of {{Kepler Stars}}},
  author = {Morton, Timothy D. and Winn, Joshua N.},
  year = {2014},
  month = nov,
  volume = {796},
  pages = {47},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/796/1/47},
  abstract = {The stellar obliquity of a transiting planetary system can be constrained by combining measurements of the star's rotation period, radius, and projected rotational velocity. Here, we present a hierarchical Bayesian technique for recovering the obliquity distribution of a population of transiting planetary systems and apply it to a sample of 70 Kepler objects of interest. With {$\approx$}95\% confidence, we find that the obliquities of stars with only a single detected transiting planet are systematically larger than those with multiple detected transiting planets. This suggests that a substantial fraction of Kepler's single-transiting systems represent dynamically hotter, less orderly systems than the "pancake-flat" multiple-transiting systems.},
  journal = {ApJ},
  keywords = {methods: statistical,planetary systems,planets and satellites: general}
}

@article{Morton2015,
  title = {Isochrones: {{Stellar}} Model Grid Package},
  shorttitle = {Isochrones},
  author = {Morton, Timothy D.},
  year = {2015},
  month = mar,
  pages = {ascl:1503.010},
  abstract = {Isochrones, written in Python, simplifies common tasks often done with stellar model grids, such as simulating synthetic stellar populations, plotting evolution tracks or isochrones, or estimating the physical properties of a star given photometric and/or spectroscopic observations.},
  journal = {Astrophys. Source Code Libr.},
  keywords = {Software}
}

@article{Mosser.Belkacem.ea2011,
  title = {The Universal Red-Giant Oscillation Pattern. {{An}} Automated Determination with {{CoRoT}} Data},
  author = {Mosser, B. and Belkacem, K. and Goupil, M. J. and Michel, E. and Elsworth, Y. and Barban, C. and Kallinger, T. and Hekker, S. and De Ridder, J. and Samadi, R. and Baudin, F. and Pinheiro, F. J. G. and Auvergne, M. and Baglin, A. and Catala, C.},
  year = {2011},
  month = jan,
  volume = {525},
  pages = {L9},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201015440},
  abstract = {Aims: The CoRoT and Kepler satellites have provided thousands of  red-giant oscillation spectra. The analysis of these spectra requires efficient methods of identifying all eigenmode parameters.  Methods: The assumption of new scaling laws allowed us to construct a theoretical oscillation pattern. We then obtained a highly precise determination of the large separation by correlating the observed patterns with this reference. Results: We demonstrate that this pattern is universal and are able to unambiguously assign the eigenmode radial orders and angular degrees. This solves one of the remaining problems of asteroseismology, hence allowing precise theoretical investigation of red-giant interiors.},
  journal = {A\&A},
  keywords = {methods: analytical,methods: data analysis,stars: interiors,stars: oscillations}
}

@article{Mosser.Gehan.ea2018,
  title = {Period Spacings in Red Giants {{IV}}. {{Toward}} a Complete Description of the Mixed-Mode Pattern},
  author = {Mosser, B. and Gehan, C. and Belkacem, K. and Samadi, R. and Michel, E. and Goupil, M.-J.},
  year = {2018},
  month = oct,
  volume = {618},
  pages = {A109},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201832777},
  abstract = {Context. Oscillation modes with a mixed character, as observed in  evolved low-mass stars, are highly sensitive to the physical properties of the innermost regions. Measuring their properties is therefore extremely important to probe the core, but requires some care, due to the complexity of the mixed-mode pattern. Aims: The aim of this work is to provide a consistent description of the mixed-mode pattern of low-mass stars, based on the asymptotic expansion. We also study the variation of the gravity offset {$\varepsilon$}g with stellar evolution. Methods: We revisit previous works about mixed modes in red giants and empirically test how period spacings, rotational splittings, mixed-mode widths, and heights can be estimated in a consistent view, based on the properties of the mode inertia ratios. Results: From the asymptotic fit of the mixed-mode pattern of a large set of red giants at various evolutionary stages, we derive unbiased and precise asymptotic parameters. As the asymptotic expansion of gravity modes is verified with a precision close to the frequency resolution for stars on the red giant branch (10-4 in relative values), we can derive accurate values of the asymptotic parameters. We decipher the complex pattern in a rapidly rotating star, and explain how asymmetrical splittings can be inferred. We also revisit the stellar inclinations in two open clusters, NGC 6819 and NGC 6791: our results show that the stellar inclinations in these clusters do not have privileged orientation in the sky. The variation of the asymptotic gravity offset with stellar evolution is investigated in detail. We also derive generic properties that explain under which conditions mixed modes can be observed. Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/618/A109},
  journal = {A\&A},
  keywords = {stars: evolution,stars: interiors,stars: oscillations}
}

@article{Mosser.Vrard.ea2015,
  title = {Period Spacings in Red Giants. {{I}}. {{Disentangling}} Rotation and Revealing Core Structure Discontinuities},
  author = {Mosser, B. and Vrard, M. and Belkacem, K. and Deheuvels, S. and Goupil, M. J.},
  year = {2015},
  month = dec,
  volume = {584},
  pages = {A50},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201527075},
  abstract = {Context. Asteroseismology allows us to probe the physical conditions  inside the core of red giant stars. This process relies on the properties of the global oscillations with a mixed character that are highly sensitive to the physical properties of the core. However, overlapping rotational splittings and mixed-mode spacings result in complex structures in the mixed-mode pattern, which severely complicates its identification and the measurement of the asymptotic period spacing.  Aims: This work aims at disentangling the rotational splittings from the mixed-mode spacings in order to open the way to a fully automated analysis of large data sets. Methods: An analytical development of the mixed-mode asymptotic expansion is used to derive the period spacing between two consecutive mixed modes. The \'echelle diagrams constructed with the appropriately stretched periods are used to exhibit the structure of the gravity modes and of the rotational splittings. Results: We propose a new view of the mixed-mode oscillation pattern based on corrected periods, called stretched periods, that mimic the evenly spaced gravity-mode pattern. This provides a direct understanding of all oscillation components, even in the case of rapid rotation. In this way, the measurement of the asymptotic period spacing and the signature of the structural glitches on mixed modes can be performed easily. Conclusions: This work makes it possible to derive all seismic global parameters in an automated way, including the identification of the different rotational multiplets and the measurement of the rotational splitting, even when this splitting is significantly larger than the period spacing. Revealing buoyancy glitches provides a detailed view of the radiative core.},
  journal = {A\&A},
  keywords = {stars: evolution,stars: interiors,stars: oscillations}
}

@article{Nielsen.Davies.ea2021,
  title = {{{PBjam}}: {{A Python Package}} for {{Automating Asteroseismology}} of {{Solar}}-like {{Oscillators}}},
  shorttitle = {{{PBjam}}},
  author = {Nielsen, M. B. and Davies, G. R. and Ball, W. H. and Lyttle, A. J. and Li, T. and Hall, O. J. and Chaplin, W. J. and Gaulme, P. and Carboneau, L. and Ong, J. M. J. and Garc{\'i}a, R. A. and Mosser, B. and Roxburgh, I. W. and Corsaro, E. and Benomar, O. and Moya, A. and Lund, M. N.},
  year = {2021},
  month = feb,
  volume = {161},
  pages = {62},
  issn = {0004-6256},
  doi = {10.3847/1538-3881/abcd39},
  abstract = {Asteroseismology is an exceptional tool for studying stars using the  properties of observed modes of oscillation. So far the process of performing an asteroseismic analysis of a star has remained somewhat esoteric and inaccessible to nonexperts. In this software paper we describe PBjam, an open-source Python package for analyzing the frequency spectra of solar-like oscillators in a simple but principled and automated way. The aim of PBjam is to provide a set of easy-to-use tools to extract information about the radial and quadropole oscillations in stars that oscillate like the Sun, which may then be used to infer bulk properties such as stellar mass, radius, age, or even structure. Asteroseismology and its data analysis methods are becoming increasingly important as space-based photometric observatories are producing a wealth of new data, allowing asteroseismology to be applied in a wide range of contexts such as exoplanet, stellar structure and evolution, and Galactic population studies.  * Release 1.0.0 Zenodo, doi:10.5281/zenodo.4300079.},
  author+an = {4=highlight},
  journal = {The Astronomical Journal},
  keywords = {1617,1855,1858,1864,73,Asteroseismology,Astronomy data analysis,Astronomy software,Publicly available software,Stellar oscillations}
}

@article{Nissen.SilvaAguirre.ea2017,
  title = {High-Precision Abundances of Elements in {{Kepler LEGACY}} Stars. {{Verification}} of Trends with Stellar Age},
  author = {Nissen, P. E. and Silva Aguirre, V. and {Christensen-Dalsgaard}, J. and Collet, R. and Grundahl, F. and Slumstrup, D.},
  year = {2017},
  month = dec,
  volume = {608},
  pages = {A112},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201731845},
  abstract = {Context. A previous study of solar twin stars has revealed the existence  of correlations between some abundance ratios and stellar age providing new knowledge about nucleosynthesis and Galactic chemical evolution. Aims: High-precision abundances of elements are determined for stars with asteroseismic ages in order to test the solar twin relations. Methods: HARPS-N spectra with signal-to-noise ratios S/N {$\greaterequivlnt$} 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected to have metallicities in the range - 0.15 {$<$} [ Fe / H ] {$<$} + 0.15 and ages between 1 and 7 Gyr. Stellar gravities were obtained from seismic data and effective temperatures were determined by comparing non-LTE iron abundances derived from Fe I and Fe II lines. Available non-LTE corrections were also applied when deriving abundances of the other elements. Results: The abundances of the Kepler stars support the [X/Fe]-age relations previously found for solar twins. [Mg/Fe], [Al/Fe], and [Zn/Fe] decrease by 0.1 dex over the lifetime of the Galactic thin disk due to delayed contribution of iron from Type Ia supernovae relative to prompt production of Mg, Al, and Zn in Type II supernovae. [Y/Mg] and [Y/Al], on the other hand, increase by 0.3 dex, which can be explained by an increasing contribution of s-process elements from low-mass AGB stars as time goes on. The trends of [C/Fe] and [O/Fe] are more complicated due to variations of the ratio between refractory and volatile elements among stars of similar age. Two stars with about the same age as the Sun show very different trends of [X/H] as a function of elemental condensation temperature Tc and for 16 Cyg, the two components have an abundance difference, which increases with Tc. These anomalies may be connected to planet-star interactions. Based on spectra obtained with HARPS-N@TNG under programme A33TAC\_1.Tables 1 and 2 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/608/A112},
  journal = {A\&A},
  keywords = {Galaxy: disk,Galaxy: evolution,planet-star interactions,stars: abundances,stars: fundamental parameters,stars: oscillations}
}

@article{Nsamba.Campante.ea2018,
  title = {Asteroseismic Modelling of Solar-Type Stars: Internal Systematics from Input Physics and Surface Correction Methods},
  shorttitle = {Asteroseismic Modelling of Solar-Type Stars},
  author = {Nsamba, B. and Campante, T. L. and Monteiro, M. J. P. F. G. and Cunha, M. S. and Rendle, B. M. and Reese, D. R. and Verma, K.},
  year = {2018},
  month = jul,
  volume = {477},
  pages = {5052--5063},
  doi = {10.1093/mnras/sty948},
  abstract = {Asteroseismic forward modelling techniques are being used to determine  fundamental properties (e.g. mass, radius, and age) of solar-type stars. The need to take into account all possible sources of error is of paramount importance towards a robust determination of stellar properties. We present a study of 34 solar-type stars for which high signal-to-noise asteroseismic data are available from multiyear Kepler photometry. We explore the internal systematics on the stellar properties, that is associated with the uncertainty in the input physics used to construct the stellar models. In particular, we explore the systematics arising from (i) the inclusion of the diffusion of helium and heavy elements; (ii) the uncertainty in solar metallicity mixture; and (iii) different surface correction methods used in optimization/fitting procedures. The systematics arising from comparing results of models with and without diffusion are found to be 0.5 per cent, 0.8 per cent, 2.1 per cent, and 16 per cent in mean density, radius, mass, and age, respectively. The internal systematics in age are significantly larger than the statistical uncertainties. We find the internal systematics resulting from the uncertainty in solar metallicity mixture to be 0.7 per cent in mean density, 0.5 per cent in radius, 1.4 per cent in mass, and 6.7 per cent in age. The surface correction method by Sonoi et al. and Ball \& Gizon's two-term correction produce the lowest internal systematics among the different correction methods, namely, {$\sim$}1 per cent, {$\sim$}1 per cent, {$\sim$}2 per cent, and {$\sim$}8 per cent in mean density, radius, mass, and age, respectively. Stellar masses obtained using the surface correction methods by Kjeldsen et al. and Ball \& Gizon's one-term correction are systematically higher than those obtained using frequency ratios.},
  journal = {MNRAS},
  keywords = {asteroseismology,stars: evolution,stars: fundamental parameters,stars: oscillations}
}

@article{Ohn.Kim2019,
  title = {Smooth Function Approximation by Deep Neural Networks with General Activation Functions},
  author = {Ohn, Ilsang and Kim, Yongdai},
  year = {2019},
  month = jun,
  volume = {21},
  pages = {627},
  issn = {1099-4300},
  doi = {10.3390/e21070627},
  abstract = {There has been a growing interest in expressivity of deep neural networks. However, most of the existing work about this topic focuses only on the specific activation function such as ReLU or sigmoid. In this paper, we investigate the approximation ability of deep neural networks with a broad class of activation functions. This class of activation functions includes most of frequently used activation functions. We derive the required depth, width and sparsity of a deep neural network to approximate any H\textbackslash "older smooth function upto a given approximation error for the large class of activation functions. Based on our approximation error analysis, we derive the minimax optimality of the deep neural network estimators with the general activation functions in both regression and classification problems.},
  archiveprefix = {arXiv},
  eprint = {1906.06903},
  eprinttype = {arxiv},
  journal = {Entropy},
  keywords = {Computer Science - Machine Learning,deep learning,machine learning,neural networks,Statistics - Machine Learning},
  number = {7}
}

@article{Onehag.Gustafsson.ea2014,
  title = {Abundances and Possible Diffusion of Elements in {{M}} 67 Stars},
  author = {{\"O}nehag, Anna and Gustafsson, Bengt and Korn, Andreas},
  year = {2014},
  month = feb,
  volume = {562},
  pages = {A102},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201322663},
  abstract = {Context. The rich open cluster M 67 is known to have a chemical composition close to solar and an age of about 3.5-4.8 Gyr. It offers an important opportunity to check and develop our understanding of the physics and the evolution of solar-type stars. Aims: We present a spectroscopic study at high resolution, R {$\approx$} 50 000, of 14 stars located on the main sequence, at the turn-off point, and on the early subgiant branch in the cluster in order to investigate its detailed chemical composition, for comparison with the Sun and solar twins in the solar neighbourhood, and to explore selective atomic diffusion of chemical elements as predicted by stellar-structure theory. Methods: We have obtained VLT/FLAMES-UVES spectra and analysed these strictly differentially in order to explore chemical-abundance similarities and differences between the M 67 stars and the Sun and among the M 67 stars themselves. Results: Individual abundances of 19 different chemical elements are obtained for the stars. They are found to agree very well with solar abundances, with abundance ratios closer to solar than those of most solar twins in the solar neighbourhood. An exception is Li, which shows considerable scatter among the cluster stars. There is a tendency for the cluster-star abundances to be more depleted than the abundances in the field stars in correlation with the condensation temperature of the elements, a tendency also found earlier for the Sun. Moreover, the heavy-element abundances are found to be reduced in the hotter stars and dwarfs by typically {$\leq$}0.05 dex, as compared to the abundances of the subgiants. Conclusions: The results support the hypothesis that the gas of the proto-cluster was depleted by formation and cleansing of dust before the stars formed. They also add support to the proposal that the Sun was formed in a dense stellar environment. Moreover, the observed minor reductions of heavy elements, relative to our standard star M 67-1194 and the subgiants, in the atmospheres of dwarfs and turn-off point stars seem to suggest that diffusion processes are at work in these stars, although the evidence is not compelling. Based on theoretical models, the diffusion-corrected initial metallicity of M 67 is estimated to be [Fe/H] = +0.06. Appendix A is available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {methods: observational,open clusters and associations: individual: M 67,stars: abundances,stars: atmospheres,stars: fundamental parameters,techniques: spectroscopic}
}

@book{Osaki.Shibahashi1990,
  title = {Progress of Seismology of the Sun and Stars},
  author = {Osaki, Yoji and Shibahashi, Hiromoto},
  year = {1990},
  volume = {367}
}

@article{Paquette.Pelletier.ea1986,
  title = {Diffusion Coefficients for Stellar Plasmas},
  author = {Paquette, C. and Pelletier, C. and Fontaine, G. and Michaud, G.},
  year = {1986},
  month = may,
  volume = {61},
  pages = {177--195},
  doi = {10.1086/191111},
  abstract = {The diffusion coefficients of relatively dense plasmas that are typical of white dwarf envelopes are presently computed by means of an approximate method, based on the numerical evaluation of collision integrals for a screened Coulomb potential, which becomes rigorously valid in the limit of a dilute plasma. The plasmas encountered in white dwarf envelopes are noted to be neither weakly nor strongly coupled; a comparison with the results of rigorous Monte Carlo calculations applicable at very high densities indicates, however, that the region of intermediate coupling is probably reasonably bridged. Results are presented in the form of high accuracy analytic fits for the collision integrals.},
  journal = {ApJS},
  keywords = {Boltzmann Transport Equation,Chapman-Enskog Theory,Collision Parameters,Coulomb Potential,Dense Plasmas,Diffusion Coefficient,Plasma Diffusion,Space Plasmas,Stellar Envelopes,Thermal Diffusion,White Dwarf Stars}
}

@article{Paxton.Bildsten.ea2011,
  title = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}})},
  author = {Paxton, Bill and Bildsten, Lars and Dotter, Aaron and Herwig, Falk and Lesaffre, Pierre and Timmes, Frank},
  year = {2011},
  month = jan,
  volume = {192},
  pages = {3},
  issn = {0067-0049},
  doi = {10.1088/0067-0049/192/1/3},
  abstract = {Stellar physics and evolution calculations enable a broad range of research in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a suite of open source, robust, efficient, thread-safe libraries for a wide range of applications in computational stellar astrophysics. A one-dimensional stellar evolution module, MESAstar, combines many of the numerical and physics modules for simulations of a wide range of stellar evolution scenarios ranging from very low mass to massive stars, including advanced evolutionary phases. MESAstar solves the fully coupled structure and composition equations simultaneously. It uses adaptive mesh refinement and sophisticated timestep controls, and supports shared memory parallelism based on OpenMP. State-of-the-art modules provide equation of state, opacity, nuclear reaction rates, element diffusion data, and atmosphere boundary conditions. Each module is constructed as a separate Fortran 95 library with its own explicitly defined public interface to facilitate independent development. Several detailed examples indicate the extensive verification and testing that is continuously performed and demonstrate the wide range of capabilities that MESA possesses. These examples include evolutionary tracks of very low mass stars, brown dwarfs, and gas giant planets to very old ages; the complete evolutionary track of a 1 M sun star from the pre-main sequence (PMS) to a cooling white dwarf; the solar sound speed profile; the evolution of intermediate-mass stars through the He-core burning phase and thermal pulses on the He-shell burning asymptotic giant branch phase; the interior structure of slowly pulsating B Stars and Beta Cepheids; the complete evolutionary tracks of massive stars from the PMS to the onset of core collapse; mass transfer from stars undergoing Roche lobe overflow; and the evolution of helium accretion onto a neutron star. MESA can be downloaded from the project Web site (http://mesa.sourceforge.net/).},
  journal = {ApJS},
  keywords = {methods: numerical,stars: evolution,stars: general}
}

@article{Paxton.Cantiello.ea2013,
  title = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}}): {{Planets}}, {{Oscillations}}, {{Rotation}}, and {{Massive Stars}}},
  shorttitle = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}})},
  author = {Paxton, Bill and Cantiello, Matteo and Arras, Phil and Bildsten, Lars and Brown, Edward F. and Dotter, Aaron and Mankovich, Christopher and Montgomery, M. H. and Stello, Dennis and Timmes, F. X. and Townsend, Richard},
  year = {2013},
  month = sep,
  volume = {208},
  pages = {4},
  issn = {0067-0049},
  doi = {10.1088/0067-0049/208/1/4},
  abstract = {We substantially update the capabilities of the open source software  package Modules for Experiments in Stellar Astrophysics (MESA), and its one-dimensional stellar evolution module, MESA star. Improvements in MESA star's ability to model the evolution of giant planets now extends its applicability down to masses as low as one-tenth that of Jupiter. The dramatic improvement in asteroseismology enabled by the space-based Kepler and CoRoT missions motivates our full coupling of the ADIPLS adiabatic pulsation code with MESA star. This also motivates a numerical recasting of the Ledoux criterion that is more easily implemented when many nuclei are present at non-negligible abundances. This impacts the way in which MESA star calculates semi-convective and thermohaline mixing. We exhibit the evolution of 3-8 M {$\odot$} stars through the end of core He burning, the onset of He thermal pulses, and arrival on the white dwarf cooling sequence. We implement diffusion of angular momentum and chemical abundances that enable calculations of rotating-star models, which we compare thoroughly with earlier work. We introduce a new treatment of radiation-dominated envelopes that allows the uninterrupted evolution of massive stars to core collapse. This enables the generation of new sets of supernovae, long gamma-ray burst, and pair-instability progenitor models. We substantially modify the way in which MESA star solves the fully coupled stellar structure and composition equations, and we show how this has improved the scaling of MESA's calculational speed on multi-core processors. Updates to the modules for equation of state, opacity, nuclear reaction rates, and atmospheric boundary conditions are also provided. We describe the MESA Software Development Kit that packages all the required components needed to form a unified, maintained, and well-validated build environment for MESA. We also highlight a few tools developed by the community for rapid visualization of MESA star results.},
  journal = {ApJS},
  keywords = {asteroseismology,methods: numerical,planets and satellites: physical evolution,stars: evolution,stars: massive,stars: rotation,stellar modelling}
}

@article{Paxton.Marchant.ea2015,
  title = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}}): {{Binaries}}, {{Pulsations}}, and {{Explosions}}},
  shorttitle = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}})},
  author = {Paxton, Bill and Marchant, Pablo and Schwab, Josiah and Bauer, Evan B. and Bildsten, Lars and Cantiello, Matteo and Dessart, Luc and Farmer, R. and Hu, H. and Langer, N. and Townsend, R. H. D. and Townsley, Dean M. and Timmes, F. X.},
  year = {2015},
  month = sep,
  volume = {220},
  pages = {15},
  issn = {0067-0049},
  doi = {10.1088/0067-0049/220/1/15},
  abstract = {We substantially update the capabilities of the open-source software  instrument Modules for Experiments in Stellar Astrophysics (MESA). MESA can now simultaneously evolve an interacting pair of differentially rotating stars undergoing transfer and loss of mass and angular momentum, greatly enhancing the prior ability to model binary evolution. New MESA capabilities in fully coupled calculation of nuclear networks with hundreds of isotopes now allow MESA to accurately simulate the advanced burning stages needed to construct supernova progenitor models. Implicit hydrodynamics with shocks can now be treated with MESA, enabling modeling of the entire massive star lifecycle, from pre-main-sequence evolution to the onset of core collapse and nucleosynthesis from the resulting explosion. Coupling of the GYRE non-adiabatic pulsation instrument with MESA allows for new explorations of the instability strips for massive stars while also accelerating the astrophysical use of asteroseismology data. We improve the treatment of mass accretion, giving more accurate and robust near-surface profiles. A new MESA capability to calculate weak reaction rates ``on-the-fly'' from input nuclear data allows better simulation of accretion induced collapse of massive white dwarfs and the fate of some massive stars. We discuss the ongoing challenge of chemical diffusion in the strongly coupled plasma regime, and exhibit improvements in MESA that now allow for the simulation of radiative levitation of heavy elements in hot stars. We close by noting that the MESA software infrastructure provides bit-for-bit consistency for all results across all the supported platforms, a profound enabling capability for accelerating MESA's development.},
  journal = {ApJS},
  keywords = {abundances,binaries: general,methods: numerical,nuclear reactions,nucleosynthesis,shock waves,stars: evolution,stars: oscillations}
}

@article{Paxton.Schwab.ea2018,
  title = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}}): {{Convective Boundaries}}, {{Element Diffusion}}, and {{Massive Star Explosions}}},
  shorttitle = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}})},
  author = {Paxton, Bill and Schwab, Josiah and Bauer, Evan B. and Bildsten, Lars and Blinnikov, Sergei and Duffell, Paul and Farmer, R. and Goldberg, Jared A. and Marchant, Pablo and Sorokina, Elena and Thoul, Anne and Townsend, Richard H. D. and Timmes, F. X.},
  year = {2018},
  month = feb,
  volume = {234},
  pages = {34},
  issn = {0067-0049},
  doi = {10.3847/1538-4365/aaa5a8},
  abstract = {We update the capabilities of the software instrument Modules for  Experiments in Stellar Astrophysics (MESA) and enhance its ease of use and availability. Our new approach to locating convective boundaries is consistent with the physics of convection, and yields reliable values of the convective-core mass during both hydrogen- and helium-burning phases. Stars with M{$<$} 8 M{$\odot$} become white dwarfs and cool to the point where the electrons are degenerate and the ions are strongly coupled, a realm now available to study with MESA due to improved treatments of element diffusion, latent heat release, and blending of equations of state. Studies of the final fates of massive stars are extended in MESA by our addition of an approximate Riemann solver that captures shocks and conserves energy to high accuracy during dynamic epochs. We also introduce a 1D capability for modeling the effects of Rayleigh-Taylor instabilities that, in combination with the coupling to a public version of the STELLA radiation transfer instrument, creates new avenues for exploring Type II supernova properties. These capabilities are exhibited with exploratory models of pair-instability supernovae, pulsational pair-instability supernovae, and the formation of stellar-mass black holes. The applicability of MESA is now widened by the capability to import multidimensional hydrodynamic models into MESA. We close by introducing software modules for handling floating point exceptions and stellar model optimization, as well as four new software tools - MESA-Web, MESA-Docker, pyMESA, and mesastar.org - to enhance MESA's education and research impact.},
  journal = {ApJS},
  keywords = {convection,diffusion,hydrodynamics,methods: numerical,stars: evolution,supernovae: general}
}

@article{Paxton.Smolec.ea2019,
  title = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}}): {{Pulsating Variable Stars}}, {{Rotation}}, {{Convective Boundaries}}, and {{Energy Conservation}}},
  shorttitle = {Modules for {{Experiments}} in {{Stellar Astrophysics}} ({{MESA}})},
  author = {Paxton, Bill and Smolec, R. and Schwab, Josiah and Gautschy, A. and Bildsten, Lars and Cantiello, Matteo and Dotter, Aaron and Farmer, R. and Goldberg, Jared A. and Jermyn, Adam S. and Kanbur, S. M. and Marchant, Pablo and Thoul, Anne and Townsend, Richard H. D. and Wolf, William M. and Zhang, Michael and Timmes, F. X.},
  year = {2019},
  month = jul,
  volume = {243},
  pages = {10},
  issn = {0067-0049},
  doi = {10.3847/1538-4365/ab2241},
  abstract = {We update the capabilities of the open-knowledge software instrument  Modules for Experiments in Stellar Astrophysics (MESA). RSP is a new functionality in MESAstar that models the nonlinear radial stellar pulsations that characterize RR Lyrae, Cepheids, and other classes of variable stars. We significantly enhance numerical energy conservation capabilities, including during mass changes. For example, this enables calculations through the He flash that conserve energy to better than 0.001\%. To improve the modeling of rotating stars in MESA, we introduce a new approach to modifying the pressure and temperature equations of stellar structure, as well as a formulation of the projection effects of gravity darkening. A new scheme for tracking convective boundaries yields reliable values of the convective core mass and allows the natural emergence of adiabatic semiconvection regions during both core hydrogen- and helium-burning phases. We quantify the parallel performance of MESA on current-generation multicore architectures and demonstrate improvements in the computational efficiency of radiative levitation. We report updates to the equation of state and nuclear reaction physics modules. We briefly discuss the current treatment of fallback in core-collapse supernova models and the thermodynamic evolution of supernova explosions. We close by discussing the new MESA Testhub software infrastructure to enhance source code development.},
  journal = {ApJS},
  keywords = {stars: evolution,stars: general,stars: interiors,stars: oscillations:  including pulsations,stars: rotation,stars: variables: general}
}

@article{Peimbert.Peimbert.ea2016,
  title = {The Primordial Helium Abundance and the Number of Neutrino Families},
  author = {Peimbert, A. and Peimbert, M. and Luridiana, V.},
  year = {2016},
  month = oct,
  volume = {52},
  pages = {419--424},
  abstract = {Based on observations of HII regions and on the new computations of the recombination coefficients of the HeI lines by Porter el al. we obtain a primordial helium abundance by mass of Y\_P = 0.2446 {$\pm$} 0.0029. We consider thirteen sources of error for the Y\_P determination; some of them are mainly due to systematic effects, while the rest are mainly due to statistical effects. We compare our results with other determinations of Y\_P present in the literature. Combining our Y\_P value with computations of primordial nucleosynthesis we find a number of neutrino species \{N\_\{eff\}=2.90{$\pm$} 0.22\}, and a neutron mean life {$\tau\_\lbrace\nu\rbrace$}=872{$\pm$} 14s.},
  journal = {Rev. Mex. Astron. Astrofisica},
  keywords = {early universe,galaxies: abundances,galaxies: ISM,H II regions,ISM: abundances}
}

@article{Peimbert2008,
  ids = {Peimbert2008a},
  title = {The {{Primordial Helium Abundance}}},
  author = {Peimbert, Manuel},
  year = {2008},
  month = nov,
  pages = {arXiv:0811.2980},
  abstract = {I present a brief review on the determination of the primordial helium abundance by unit mass, Yp. I discuss the importance of the primordial helium abundance in: (a) cosmology, (b) testing the standard big bang nucleosynthesis, (c) studying the physical conditions in H II regions, (d) providing the initial conditions for stellar evolution models, and (e) testing the galactic chemical evolution models.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:0811.2980},
  eprint = {0811.2980},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Astrophysics},
  primaryclass = {astro-ph}
}

@article{Pinsonneault.An.ea2012,
  ids = {Pinsonneault.An.ea2012a},
  title = {A {{Revised Effective Temperature Scale}} for the {{Kepler Input Catalog}}},
  author = {Pinsonneault, Marc H. and An, Deokkeun and {Molenda-{\.Z}akowicz}, Joanna and Chaplin, William J. and Metcalfe, Travis S. and Bruntt, Hans},
  year = {2012},
  month = apr,
  volume = {199},
  pages = {30},
  issn = {0067-0049},
  doi = {10.1088/0067-0049/199/2/30},
  abstract = {We present a catalog of revised effective temperatures for stars observed in long-cadence mode in the Kepler Input Catalog (KIC). We use Sloan Digital Sky Survey (SDSS) griz filters tied to the fundamental temperature scale. Polynomials for griz color-temperature relations are presented, along with correction terms for surface gravity effects, metallicity, and statistical corrections for binary companions or blending. We compare our temperature scale to the published infrared flux method (IRFM) scale for VTJKs in both open clusters and the Kepler fields. We find good agreement overall, with some deviations between (J - Ks )-based temperatures from the IRFM and both SDSS filter and other diagnostic IRFM color-temperature relationships above 6000 K. For field dwarfs, we find a mean shift toward hotter temperatures relative to the KIC, of order 215 K, in the regime where the IRFM scale is well defined (4000 K to 6500 K). This change is of comparable magnitude in both color systems and in spectroscopy for stars with T eff below 6000 K. Systematic differences between temperature estimators appear for hotter stars, and we define corrections to put the SDSS temperatures on the IRFM scale for them. When the theoretical dependence on gravity is accounted for, we find a similar temperature scale offset between the fundamental and KIC scales for giants. We demonstrate that statistical corrections to color-based temperatures from binaries are significant. Typical errors, mostly from uncertainties in extinction, are of order 100 K. Implications for other applications of the KIC are discussed.},
  journal = {ApJS},
  keywords = {stars: fundamental parameters}
}

@article{Pinsonneault.Elsworth.ea2014,
  title = {The {{APOKASC Catalog}}: {{An Asteroseismic}} and {{Spectroscopic Joint Survey}} of {{Targets}} in the {{Kepler Fields}}},
  shorttitle = {The {{APOKASC Catalog}}},
  author = {Pinsonneault, Marc H. and Elsworth, Yvonne and Epstein, Courtney and Hekker, Saskia and M{\'e}sz{\'a}ros, Sz. and Chaplin, William J. and Johnson, Jennifer A. and Garc{\'i}a, Rafael A. and Holtzman, Jon and Mathur, Savita and Garc{\'i}a P{\'e}rez, Ana and Silva Aguirre, Victor and Girardi, L{\'e}o and Basu, Sarbani and Shetrone, Matthew and Stello, Dennis and Allende Prieto, Carlos and An, Deokkeun and Beck, Paul and Beers, Timothy C. and Bizyaev, Dmitry and Bloemen, Steven and Bovy, Jo and Cunha, Katia and De Ridder, Joris and Frinchaboy, Peter M. and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Gilliland, Ronald and Harding, Paul and Hearty, Fred R. and Huber, Daniel and Ivans, Inese and Kallinger, Thomas and Majewski, Steven R. and Metcalfe, Travis S. and Miglio, Andrea and Mosser, Benoit and Muna, Demitri and Nidever, David L. and Schneider, Donald P. and Serenelli, Aldo and Smith, Verne V. and Tayar, Jamie and Zamora, Olga and Zasowski, Gail},
  year = {2014},
  month = dec,
  volume = {215},
  pages = {19},
  doi = {10.1088/0067-0049/215/2/19},
  abstract = {We present the first APOKASC catalog of spectroscopic and asteroseismic  properties of 1916 red giants observed in the Kepler fields. The spectroscopic parameters provided from the Apache Point Observatory Galactic Evolution Experiment project are complemented with asteroseismic surface gravities, masses, radii, and mean densities determined by members of the Kepler Asteroseismology Science Consortium. We assess both random and systematic sources of error and include a discussion of sample selection for giants in the Kepler fields. Total uncertainties in the main catalog properties are of the order of 80 K in T eff, 0.06 dex in [M/H], 0.014 dex in log g, and 12\% and 5\% in mass and radius, respectively; these reflect a combination of systematic and random errors. Asteroseismic surface gravities are substantially more precise and accurate than spectroscopic ones, and we find good agreement between their mean values and the calibrated spectroscopic surface gravities. There are, however, systematic underlying trends with T eff and log g. Our effective temperature scale is between 0 and 200 K cooler than that expected from the infrared flux method, depending on the adopted extinction map, which provides evidence for a lower value on average than that inferred for the Kepler Input Catalog (KIC). We find a reasonable correspondence between the photometric KIC and spectroscopic APOKASC metallicity scales, with increased dispersion in KIC metallicities as the absolute metal abundance decreases, and offsets in T eff and log g consistent with those derived in the literature. We present mean fitting relations between APOKASC and KIC observables and discuss future prospects, strengths, and limitations of the catalog data.},
  journal = {ApJS},
  keywords = {catalogs,stars: abundances,stars: fundamental parameters,stars: oscillations: including pulsations,surveys}
}

@article{Pinsonneault.Elsworth.ea2018,
  title = {The {{Second APOKASC Catalog}}: {{The Empirical Approach}}},
  shorttitle = {The {{Second APOKASC Catalog}}},
  author = {Pinsonneault, Marc H. and Elsworth, Yvonne P. and Tayar, Jamie and Serenelli, Aldo and Stello, Dennis and Zinn, Joel and Mathur, Savita and Garc{\'i}a, Rafael A. and Johnson, Jennifer A. and Hekker, Saskia and Huber, Daniel and Kallinger, Thomas and M{\'e}sz{\'a}ros, Szabolcs and Mosser, Benoit and Stassun, Keivan and Girardi, L{\'e}o and Rodrigues, Tha{\'i}se S. and Silva Aguirre, Victor and An, Deokkeun and Basu, Sarbani and Chaplin, William J. and Corsaro, Enrico and Cunha, Katia and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Holtzman, Jon and J{\"o}nsson, Henrik and Shetrone, Matthew and Smith, Verne V. and Sobeck, Jennifer S. and Stringfellow, Guy S. and Zamora, Olga and Beers, Timothy C. and {Fern{\'a}ndez-Trincado}, J. G. and Frinchaboy, Peter M. and Hearty, Fred R. and Nitschelm, Christian},
  year = {2018},
  month = dec,
  volume = {239},
  pages = {32},
  doi = {10.3847/1538-4365/aaebfd},
  abstract = {We present a catalog of stellar properties for a large sample of 6676 evolved stars with Apache Point Observatory Galactic Evolution Experiment spectroscopic parameters and Kepler asteroseismic data analyzed using five independent techniques. Our data include evolutionary state, surface gravity, mean density, mass, radius, age, and the spectroscopic and asteroseismic measurements used to derive them. We employ a new empirical approach for combining asteroseismic measurements from different methods, calibrating the inferred stellar parameters, and estimating uncertainties. With high statistical significance, we find that asteroseismic parameters inferred from the different pipelines have systematic offsets that are not removed by accounting for differences in their solar reference values. We include theoretically motivated corrections to the large frequency spacing ({$\Delta\nu$}) scaling relation, and we calibrate the zero-point of the frequency of the maximum power ({$\nu$} max) relation to be consistent with masses and radii for members of star clusters. For most targets, the parameters returned by different pipelines are in much better agreement than would be expected from the pipeline-predicted random errors, but 22\% of them had at least one method not return a result and a much larger measurement dispersion. This supports the usage of multiple analysis techniques for asteroseismic stellar population studies. The measured dispersion in mass estimates for fundamental calibrators is consistent with our error model, which yields median random and systematic mass uncertainties for RGB stars of order 4\%. Median random and systematic mass uncertainties are at the 9\% and 8\% level, respectively, for red clump stars.},
  journal = {ApJS},
  keywords = {stars: abundances,stars: fundamental parameters,stars: oscillations: including pulsations}
}

@article{Pitrou.Coc.ea2018,
  title = {Precision Big Bang Nucleosynthesis with Improved {{Helium}}-4 Predictions},
  author = {Pitrou, Cyril and Coc, Alain and Uzan, Jean-Philippe and Vangioni, Elisabeth},
  year = {2018},
  month = sep,
  volume = {754},
  pages = {1--66},
  issn = {0370-1573},
  doi = {10.1016/j.physrep.2018.04.005},
  abstract = {Primordial nucleosynthesis is one of the three historical evidences for the big bang model, together with the expansion of the universe and the cosmic microwave background. There is a good global agreement between the computed primordial abundances of helium-4, deuterium, helium-3 and their values deduced from observations. Now that the number of neutrino families and the baryonic densities have been fixed by laboratory measurements or CMB observations, the model has no free parameter and its predictions are rigid. Since this is the earliest cosmic process for which we a priori know all the physics involved, departure from its predictions could provide hints or constraints on new physics or astrophysics in the early universe. Precision on primordial abundances deduced from observations has recently been drastically improved and reach the percent level for both deuterium and helium-4. Accordingly, the BBN predictions should reach the same level of precision. For most isotopes, the dominant sources of uncertainty come from those on the laboratory thermonuclear reactions. This article focuses on helium-4 whose predicted primordial abundance depends essentially on weak interactions which control the neutron-proton ratio. The rates of the various weak interaction processes depend on the experimentally measured neutron lifetime, but also includes numerous corrections that we thoroughly investigate here. They are the radiative, zero-temperature, corrections, finite nucleon mass corrections, finite temperature radiative corrections, weak-magnetism, and QED plasma effects, which are for the first time all included and calculated in a self consistent way, allowing to take into account the correlations between them, and verifying that all satisfy detailed balance. Finally, we include the incomplete neutrino decoupling and claim to reach a 10-4 accuracy on the helium-4 predicted mass fraction of 0 . 24709 {$\pm$} 0 . 00017 (when including the uncertainty on the neutron lifetime). In addition, we provide a Mathematica primordial nucleosynthesis code that incorporates, not only these corrections but also a full network of reactions, using the best available thermonuclear reaction rates, allowing the predictions of primordial abundances of helium-4, deuterium, helium-3 and lithium-7 but also of heavier isotopes up to the CNO region.},
  journal = {Phys. Rep.}
}

@article{PlanckCollaboration.Ade.ea2016,
  title = {Planck 2015 Results. {{XIII}}. {{Cosmological}} Parameters},
  author = {{Planck Collaboration} and Ade, P. A. R. and Aghanim, N. and Arnaud, M. and Ashdown, M. and Aumont, J. and Baccigalupi, C. and Banday, A. J. and Barreiro, R. B. and Bartlett, J. G. and Bartolo, N. and Battaner, E. and Battye, R. and Benabed, K. and Beno{\^i}t, A. and {Benoit-L{\'e}vy}, A. and Bernard, J.-P. and Bersanelli, M. and Bielewicz, P. and Bock, J. J. and Bonaldi, A. and Bonavera, L. and Bond, J. R. and Borrill, J. and Bouchet, F. R. and Boulanger, F. and Bucher, M. and Burigana, C. and Butler, R. C. and Calabrese, E. and Cardoso, J.-F. and Catalano, A. and Challinor, A. and Chamballu, A. and Chary, R.-R. and Chiang, H. C. and Chluba, J. and Christensen, P. R. and Church, S. and Clements, D. L. and Colombi, S. and Colombo, L. P. L. and Combet, C. and Coulais, A. and Crill, B. P. and Curto, A. and Cuttaia, F. and Danese, L. and Davies, R. D. and Davis, R. J. and {de Bernardis}, P. and {de Rosa}, A. and {de Zotti}, G. and Delabrouille, J. and D{\'e}sert, F.-X. and Di Valentino, E. and Dickinson, C. and Diego, J. M. and Dolag, K. and Dole, H. and Donzelli, S. and Dor{\'e}, O. and Douspis, M. and Ducout, A. and Dunkley, J. and Dupac, X. and Efstathiou, G. and Elsner, F. and En{\ss}lin, T. A. and Eriksen, H. K. and Farhang, M. and Fergusson, J. and Finelli, F. and Forni, O. and Frailis, M. and Fraisse, A. A. and Franceschi, E. and Frejsel, A. and Galeotta, S. and Galli, S. and Ganga, K. and Gauthier, C. and Gerbino, M. and Ghosh, T. and Giard, M. and {Giraud-H{\'e}raud}, Y. and Giusarma, E. and Gjerl{\o}w, E. and {Gonz{\'a}lez-Nuevo}, J. and G{\'o}rski, K. M. and Gratton, S. and Gregorio, A. and Gruppuso, A. and Gudmundsson, J. E. and Hamann, J. and Hansen, F. K. and Hanson, D. and Harrison, D. L. and Helou, G. and {Henrot-Versill{\'e}}, S. and {Hern{\'a}ndez-Monteagudo}, C. and Herranz, D. and Hildebrandt, S. R. and Hivon, E. and Hobson, M. and Holmes, W. A. and Hornstrup, A. and Hovest, W. and Huang, Z. and Huffenberger, K. M. and Hurier, G. and Jaffe, A. H. and Jaffe, T. R. and Jones, W. C. and Juvela, M. and Keih{\"a}nen, E. and Keskitalo, R. and Kisner, T. S. and Kneissl, R. and Knoche, J. and Knox, L. and Kunz, M. and {Kurki-Suonio}, H. and Lagache, G. and L{\"a}hteenm{\"a}ki, A. and Lamarre, J.-M. and Lasenby, A. and Lattanzi, M. and Lawrence, C. R. and Leahy, J. P. and Leonardi, R. and Lesgourgues, J. and Levrier, F. and Lewis, A. and Liguori, M. and Lilje, P. B. and {Linden-V{\o}rnle}, M. and {L{\'o}pez-Caniego}, M. and Lubin, P. M. and {Mac{\'i}as-P{\'e}rez}, J. F. and Maggio, G. and Maino, D. and Mandolesi, N. and Mangilli, A. and Marchini, A. and Maris, M. and Martin, P. G. and Martinelli, M. and {Mart{\'i}nez-Gonz{\'a}lez}, E. and Masi, S. and Matarrese, S. and McGehee, P. and Meinhold, P. R. and Melchiorri, A. and Melin, J.-B. and Mendes, L. and Mennella, A. and Migliaccio, M. and Millea, M. and Mitra, S. and {Miville-Desch{\^e}nes}, M.-A. and Moneti, A. and Montier, L. and Morgante, G. and Mortlock, D. and Moss, A. and Munshi, D. and Murphy, J. A. and Naselsky, P. and Nati, F. and Natoli, P. and Netterfield, C. B. and {N{\o}rgaard-Nielsen}, H. U. and Noviello, F. and Novikov, D. and Novikov, I. and Oxborrow, C. A. and Paci, F. and Pagano, L. and Pajot, F. and Paladini, R. and Paoletti, D. and Partridge, B. and Pasian, F. and Patanchon, G. and Pearson, T. J. and Perdereau, O. and Perotto, L. and Perrotta, F. and Pettorino, V. and Piacentini, F. and Piat, M. and Pierpaoli, E. and Pietrobon, D. and Plaszczynski, S. and Pointecouteau, E. and Polenta, G. and Popa, L. and Pratt, G. W. and Pr{\'e}zeau, G. and Prunet, S. and Puget, J.-L. and Rachen, J. P. and Reach, W. T. and Rebolo, R. and Reinecke, M. and Remazeilles, M. and Renault, C. and Renzi, A. and Ristorcelli, I. and Rocha, G. and Rosset, C. and Rossetti, M. and Roudier, G. and {Rouill{\'e} d'Orfeuil}, B. and {Rowan-Robinson}, M. and {Rubi{\~n}o-Mart{\'i}n}, J. A. and Rusholme, B. and Said, N. and Salvatelli, V. and Salvati, L. and Sandri, M. and Santos, D. and Savelainen, M. and Savini, G. and Scott, D. and Seiffert, M. D. and Serra, P. and Shellard, E. P. S. and Spencer, L. D. and Spinelli, M. and Stolyarov, V. and Stompor, R. and Sudiwala, R. and Sunyaev, R. and Sutton, D. and {Suur-Uski}, A.-S. and Sygnet, J.-F. and Tauber, J. A. and Terenzi, L. and Toffolatti, L. and Tomasi, M. and Tristram, M. and Trombetti, T. and Tucci, M. and Tuovinen, J. and T{\"u}rler, M. and Umana, G. and Valenziano, L. and Valiviita, J. and Van Tent, F. and Vielva, P. and Villa, F. and Wade, L. A. and Wandelt, B. D. and Wehus, I. K. and White, M. and White, S. D. M. and Wilkinson, A. and Yvon, D. and Zacchei, A. and Zonca, A.},
  year = {2016},
  month = sep,
  volume = {594},
  pages = {A13},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201525830},
  abstract = {This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter {$\Lambda$}CDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted "base {$\Lambda$}CDM" in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H0 = (67.8 {$\pm$} 0.9) km s-1Mpc-1, a matter density parameter {$\Omega$}m = 0.308 {$\pm$} 0.012, and a tilted scalar spectral index with ns = 0.968 {$\pm$} 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68\% confidence limits on measured parameters and 95\% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of {$\tau$} = 0.066 {$\pm$} 0.016, corresponding to a reionization redshift of z\_re=8.8+1.7-1.4. These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base {$\Lambda$}CDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find Neff = 3.15 {$\pm$} 0.23 for the effective number of relativistic degrees of freedom, consistent with the value Neff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to {$\sum$} m{$\nu$} {$<$} 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with | {$\Omega$}K | {$<$} 0.005. Adding a tensor component as a single-parameter extension to base {$\Lambda$}CDM we find an upper limit on the tensor-to-scalar ratio of r0.002{$<$} 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r0.002 {$<$} 0.09 and disfavours inflationarymodels with a V({$\varphi$}) {$\propto$} {$\varphi$}2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = -1.006 {$\pm$} 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base {$\Lambda$}CDM cosmology are in excellent agreement with observations. We also constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base {$\Lambda$}CDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base {$\Lambda$}CDM cosmology. Apart from these tensions, the base {$\Lambda$}CDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.},
  journal = {A\&A},
  keywords = {cosmic background radiation,cosmological parameters,cosmology: observations,cosmology: theory}
}

@article{Qian1999,
  title = {On the Momentum Term in Gradient Descent Learning Algorithms},
  author = {Qian, Ning},
  year = {1999},
  month = jan,
  volume = {12},
  pages = {145--151},
  issn = {0893-6080},
  doi = {10.1016/S0893-6080(98)00116-6},
  abstract = {A momentum term is usually included in the simulations of connectionist learning algorithms. Although it is well known that such a term greatly improves the speed of learning, there have been few rigorous studies of its mechanisms. In this paper, I show that in the limit of continuous time, the momentum parameter is analogous to the mass of Newtonian particles that move through a viscous medium in a conservative force field. The behavior of the system near a local minimum is equivalent to a set of coupled and damped harmonic oscillators. The momentum term improves the speed of convergence by bringing some eigen components of the system closer to critical damping. Similar results can be obtained for the discrete time case used in computer simulations. In particular, I derive the bounds for convergence on learning-rate and momentum parameters, and demonstrate that the momentum term can increase the range of learning rate over which the system converges. The optimal condition for convergence is also analyzed.},
  journal = {Neural Netw.},
  keywords = {Critical damping,Damped harmonic oscillator,Gradient descent learning algorithm,Learning rate,Momentum,Speed of convergence},
  language = {en},
  number = {1}
}

@article{Ramachandran.Zoph.ea2017,
  ids = {Ramachandran.Zoph.ea2017a},
  title = {Searching for {{Activation Functions}}},
  author = {Ramachandran, Prajit and Zoph, Barret and Le, Quoc V.},
  year = {2017},
  month = oct,
  pages = {arXiv:1710.05941},
  abstract = {The choice of activation functions in deep networks has a significant effect on the training dynamics and task performance. Currently, the most successful and widely-used activation function is the Rectified Linear Unit (ReLU). Although various hand-designed alternatives to ReLU have been proposed, none have managed to replace it due to inconsistent gains. In this work, we propose to leverage automatic search techniques to discover new activation functions. Using a combination of exhaustive and reinforcement learning-based search, we discover multiple novel activation functions. We verify the effectiveness of the searches by conducting an empirical evaluation with the best discovered activation function. Our experiments show that the best discovered activation function, \$f(x) = x \textbackslash cdot \textbackslash text\{sigmoid\}(\textbackslash beta x)\$, which we name Swish, tends to work better than ReLU on deeper models across a number of challenging datasets. For example, simply replacing ReLUs with Swish units improves top-1 classification accuracy on ImageNet by 0.9\textbackslash\% for Mobile NASNet-A and 0.6\textbackslash\% for Inception-ResNet-v2. The simplicity of Swish and its similarity to ReLU make it easy for practitioners to replace ReLUs with Swish units in any neural network.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1710.05941},
  eprint = {1710.05941},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Computer Science - Computer Vision and Pattern Recognition,Computer Science - Machine Learning,Computer Science - Neural and Evolutionary Computing},
  primaryclass = {cs.NE}
}

@article{Rauer.Catala.ea2014,
  title = {The {{PLATO}} 2.0 Mission},
  author = {Rauer, H. and Catala, C. and Aerts, C. and Appourchaux, T. and Benz, W. and Brandeker, A. and {Christensen-Dalsgaard}, J. and Deleuil, M. and Gizon, L. and Goupil, M.-J. and G{\"u}del, M. and {Janot-Pacheco}, E. and {Mas-Hesse}, M. and Pagano, I. and Piotto, G. and Pollacco, D. and Santos, {\.C}. and Smith, A. and Su{\'a}rez, J.-C. and Szab{\'o}, R. and Udry, S. and Adibekyan, V. and Alibert, Y. and Almenara, J.-M. and {Amaro-Seoane}, P. and Eiff, M. Ammler-von and Asplund, M. and Antonello, E. and Barnes, S. and Baudin, F. and Belkacem, K. and Bergemann, M. and Bihain, G. and Birch, A. C. and Bonfils, X. and Boisse, I. and Bonomo, A. S. and Borsa, F. and Brand{\~a}o, I. M. and Brocato, E. and Brun, S. and Burleigh, M. and Burston, R. and Cabrera, J. and Cassisi, S. and Chaplin, W. and Charpinet, S. and Chiappini, C. and Church, R. P. and Csizmadia, Sz. and Cunha, M. and Damasso, M. and Davies, M. B. and Deeg, H. J. and D{\'i}az, R. F. and Dreizler, S. and Dreyer, C. and Eggenberger, P. and Ehrenreich, D. and Eigm{\"u}ller, P. and Erikson, A. and Farmer, R. and Feltzing, S. and {de Oliveira Fialho}, F. and Figueira, P. and Forveille, T. and Fridlund, M. and Garc{\'i}a, R. A. and Giommi, P. and Giuffrida, G. and Godolt, M. and {Gomes da Silva}, J. and Granzer, T. and Grenfell, J. L. and {Grotsch-Noels}, A. and G{\"u}nther, E. and Haswell, C. A. and Hatzes, A. P. and H{\'e}brard, G. and Hekker, S. and Helled, R. and Heng, K. and Jenkins, J. M. and Johansen, A. and Khodachenko, M. L. and Kislyakova, K. G. and Kley, W. and Kolb, U. and Krivova, N. and Kupka, F. and Lammer, H. and Lanza, A. F. and Lebreton, Y. and Magrin, D. and {Marcos-Arenal}, P. and Marrese, P. M. and Marques, J. P. and Martins, J. and Mathis, S. and Mathur, S. and Messina, S. and Miglio, A. and Montalban, J. and Montalto, M. and Monteiro, M. J. P. F. G. and Moradi, H. and Moravveji, E. and Mordasini, C. and Morel, T. and Mortier, A. and Nascimbeni, V. and Nelson, R. P. and Nielsen, M. B. and Noack, L. and Norton, A. J. and Ofir, A. and Oshagh, M. and Ouazzani, R.-M. and P{\'a}pics, P. and Parro, V. C. and Petit, P. and Plez, B. and Poretti, E. and Quirrenbach, A. and Ragazzoni, R. and Raimondo, G. and Rainer, M. and Reese, D. R. and Redmer, R. and Reffert, S. and {Rojas-Ayala}, B. and Roxburgh, I. W. and Salmon, S. and Santerne, A. and Schneider, J. and Schou, J. and Schuh, S. and Schunker, H. and {Silva-Valio}, A. and Silvotti, R. and Skillen, I. and Snellen, I. and Sohl, F. and Sousa, S. G. and Sozzetti, A. and Stello, D. and Strassmeier, K. G. and {\v S}vanda, M. and Szab{\'o}, Gy. M. and Tkachenko, A. and Valencia, D. and Van Grootel, V. and Vauclair, S. D. and Ventura, P. and Wagner, F. W. and Walton, N. A. and Weingrill, J. and Werner, S. C. and Wheatley, P. J. and Zwintz, K.},
  year = {2014},
  month = nov,
  volume = {38},
  pages = {249--330},
  issn = {0922-6435},
  doi = {10.1007/s10686-014-9383-4},
  abstract = {PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4-16 mag). It focusses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 \%, 4-10 \% and 10 \% for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 \% of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA's Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science.},
  journal = {Exp. Astron.},
  keywords = {Asteroseismology,Exoplanetary science,Exoplanets,Stellar science,Transit survey}
}

@article{Reese.Chaplin.ea2016,
  title = {{{SpaceInn}} Hare-and-Hounds Exercise: {{Estimation}} of Stellar Properties Using Space-Based Asteroseismic Data},
  shorttitle = {{{SpaceInn}} Hare-and-Hounds Exercise},
  author = {Reese, D. R. and Chaplin, W. J. and Davies, G. R. and Miglio, A. and Antia, H. M. and Ball, W. H. and Basu, S. and Buldgen, G. and {Christensen-Dalsgaard}, J. and Coelho, H. R. and Hekker, S. and Houdek, G. and Lebreton, Y. and Mazumdar, A. and Metcalfe, T. S. and Silva Aguirre, V. and Stello, D. and Verma, K.},
  year = {2016},
  month = jul,
  volume = {592},
  pages = {A14},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201527987},
  abstract = {Context. Detailed oscillation spectra comprising individual frequencies  for numerous solar-type stars and red giants are either currently available, e.g. courtesy of the CoRoT, Kepler, and K2 missions, or will become available with the upcoming NASA TESS and ESA PLATO 2.0 missions. The data can lead to a precise characterisation of these stars thereby improving our understanding of stellar evolution, exoplanetary systems, and the history of our galaxy. Aims: Our goal is to test and compare different methods for obtaining stellar properties from oscillation frequencies and spectroscopic constraints. Specifically, we would like to evaluate the accuracy of the results and reliability of the associated error bars, and to see where there is room for improvement. Methods: In the context of the SpaceInn network, we carried out a hare-and-hounds exercise in which one group, the hares, simulated observations of oscillation spectra for a set of ten artificial solar-type stars, and a number of hounds applied various methods for characterising these stars based on the data produced by the hares. Most of the hounds fell into two main groups. The first group used forward modelling (I.e. applied various search/optimisation algorithms in a stellar parameter space) whereas the second group relied on acoustic glitch signatures. Results: Results based on the forward modelling approach were accurate to 1.5\% (radius), 3.9\% (mass), 23\% (age), 1.5\% (surface gravity), and 1.8\% (mean density), as based on the root mean square difference. Individual hounds reached different degrees of accuracy, some of which were substantially better than the above average values. For the two 1M{$\odot$} stellar targets, the accuracy on the age is better than 10\% thereby satisfying the requirements for the PLATO 2.0 mission. High stellar masses and atomic diffusion (which in our models does not include the effects of radiative accelerations) proved to be sources of difficulty. The average accuracies for the acoustic radii of the base of the convection zone, the He II ionisation, and the {$\Gamma$}1 peak located between the two He ionisation zones were 17\%, 2.4\%, and 1.9\%, respectively. The results from the forward modelling were on average more accurate than those from the glitch fitting analysis as the latter seemed to be affected by aliasing problems for some of the targets.  Conclusions: Our study indicates that forward modelling is the most accurate way of interpreting the pulsation spectra of solar-type stars. However, given its model-dependent nature, this method needs to be complemented by model-independent results from, e.g. glitch analysis. Furthermore, our results indicate that global rather than local optimisation algorithms should be used in order to obtain robust error bars.},
  journal = {A\&A},
  keywords = {stars: interiors,stars: oscillations}
}

@article{Ribas.Jordi.ea2000,
  title = {Chemical Composition of Eclipsing Binaries: A New Approach to the Helium-to-Metal Enrichment Ratio},
  shorttitle = {Chemical Composition of Eclipsing Binaries},
  author = {Ribas, Ignasi and Jordi, Carme and Torra, Jordi and Gim{\'e}nez, {\'A}lvaro},
  year = {2000},
  month = mar,
  volume = {313},
  pages = {99--111},
  issn = {0035-8711},
  doi = {10.1046/j.1365-8711.2000.03195.x},
  abstract = {The chemical enrichment law Y(Z) is studied by using detached  double-lined eclipsing binaries with accurate absolute dimensions and effective temperatures. A sample of 50 suitable systems was collected from the literature, and their effective temperatures were carefully re-determined. The chemical composition of each of the systems was obtained by comparison with stellar evolutionary models, under the assumption that they should fit an isochrone to the observed properties of the components. Evolutionary models covering a wide grid in Z and Y were adopted for our study. An algorithm was developed for searching the best-fitting chemical composition (and the age) for the systems, based on the minimization of a {$\chi$}2 function. The errors (and biases) of these parameters were estimated by means of Monte Carlo simulations, with special care put on the correlations existing between the errors of both components. In order to check the physical consistency of the results, we compared our metallicity values with empirical determinations, obtaining excellent coherence. The independently derived Z and Y values yielded a determination of the chemical enrichment law via weighted linear least-squares fit. Our value of the slope, {$\Delta$}Y/{$\Delta$}Z=2.2+/-0.8, is in good agreement with recent results, but it has a smaller formal error and it is free of systematic effects. Linear extrapolation of the enrichment law to zero metals leads to an estimation of the primordial helium abundance of Yp=0.225+/-0.013, possibly affected by systematics in the effective temperature determination.},
  journal = {MNRAS},
  keywords = {BINARIES: ECLIPSING,GALAXIES: ABUNDANCES,ISM: ABUNDANCES,STARS: ABUNDANCES,STARS: EVOLUTION}
}

@article{Ricker.Winn.ea2015,
  title = {Transiting {{Exoplanet Survey Satellite}} ({{TESS}})},
  author = {Ricker, George R. and Winn, Joshua N. and Vanderspek, Roland and Latham, David W. and Bakos, G{\'a}sp{\'a}r {\'A}. and Bean, Jacob L. and {Berta-Thompson}, Zachory K. and Brown, Timothy M. and Buchhave, Lars and Butler, Nathaniel R. and Butler, R. Paul and Chaplin, William J. and Charbonneau, David and {Christensen-Dalsgaard}, J{\o}rgen and Clampin, Mark and Deming, Drake and Doty, John and De Lee, Nathan and Dressing, Courtney and Dunham, Edward W. and Endl, Michael and Fressin, Francois and Ge, Jian and Henning, Thomas and Holman, Matthew J. and Howard, Andrew W. and Ida, Shigeru and Jenkins, Jon M. and Jernigan, Garrett and Johnson, John Asher and Kaltenegger, Lisa and Kawai, Nobuyuki and Kjeldsen, Hans and Laughlin, Gregory and Levine, Alan M. and Lin, Douglas and Lissauer, Jack J. and MacQueen, Phillip and Marcy, Geoffrey and McCullough, Peter R. and Morton, Timothy D. and Narita, Norio and Paegert, Martin and Palle, Enric and Pepe, Francesco and Pepper, Joshua and Quirrenbach, Andreas and Rinehart, Stephen A. and Sasselov, Dimitar and Sato, Bun'ei and Seager, Sara and Sozzetti, Alessandro and Stassun, Keivan G. and Sullivan, Peter and Szentgyorgyi, Andrew and Torres, Guillermo and Udry, Stephane and Villasenor, Joel},
  year = {2015},
  month = jan,
  volume = {1},
  pages = {014003},
  doi = {10.1117/1.JATIS.1.1.014003},
  abstract = {The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its 2-year mission, TESS will employ four wide-field optical charge-coupled device cameras to monitor at least 200,000 main-sequence dwarf stars with IC{$\approx$}4-13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from 1 month to 1 year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10 to 100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.},
  journal = {J. Astron. Telesc. Instrum. Syst.}
}

@article{Riess.Casertano.ea2018,
  title = {Milky {{Way Cepheid Standards}} for {{Measuring Cosmic Distances}} and {{Application}} to {{Gaia DR2}}: {{Implications}} for the {{Hubble Constant}}},
  shorttitle = {Milky {{Way Cepheid Standards}} for {{Measuring Cosmic Distances}} and {{Application}} to {{Gaia DR2}}},
  author = {Riess, Adam G. and Casertano, Stefano and Yuan, Wenlong and Macri, Lucas and Bucciarelli, Beatrice and Lattanzi, Mario G. and MacKenty, John W. and Bowers, J. Bradley and Zheng, WeiKang and Filippenko, Alexei V. and Huang, Caroline and Anderson, Richard I.},
  year = {2018},
  month = jul,
  volume = {861},
  pages = {126},
  doi = {10.3847/1538-4357/aac82e},
  abstract = {We present Hubble Space Telescope (HST) photometry of a selected sample  of 50 long-period, low-extinction Milky Way Cepheids measured on the same WFC3 F555W-, F814W-, and F160W-band photometric system as extragalactic Cepheids in Type Ia supernova host galaxies. These bright Cepheids were observed with the WFC3 spatial scanning mode in the optical and near-infrared to mitigate saturation and reduce pixel-to-pixel calibration errors to reach a mean photometric error of 5 mmag per observation. We use the new Gaia DR2 parallaxes and HST photometry to simultaneously constrain the cosmic distance scale and to measure the DR2 parallax zeropoint offset appropriate for Cepheids. We find the latter to be -46 {$\pm$} 13 {$\mu$}as or {$\pm$}6 {$\mu$}as for a fixed distance scale, higher than found from quasars, as expected for these brighter and redder sources. The precision of the distance scale from DR2 has been reduced by a factor of 2.5 because of the need to independently determine the parallax offset. The best-fit distance scale is 1.006 {$\pm$} 0.033, relative to the scale from Riess et al. with H 0 = 73.24 km s-1 Mpc-1 used to predict the parallaxes photometrically, and is inconsistent with the scale needed to match the Planck 2016 cosmic microwave background data combined with {$\Lambda$}CDM at the 2.9{$\sigma$} confidence level (99.6\%). At 96.5\% confidence we find that the formal DR2 errors may be underestimated as indicated. We identify additional errors associated with the use of augmented Cepheid samples utilizing ground-based photometry and discuss their likely origins. Including the DR2 parallaxes with all prior distance-ladder data raises the current tension between the late and early universe route to the Hubble constant to 3.8{$\sigma$} (99.99\%). With the final expected precision from Gaia, the sample of 50 Cepheids with HST photometry will limit to 0.5\% the contribution of the first rung of the distance ladder to the uncertainty in H 0.},
  journal = {ApJ},
  keywords = {cosmology: observations,distance scale,parallaxes}
}

@article{Rogers.Nayfonov2002,
  title = {Updated and {{Expanded OPAL Equation}}-of-{{State Tables}}: {{Implications}} for {{Helioseismology}}},
  shorttitle = {Updated and {{Expanded OPAL Equation}}-of-{{State Tables}}},
  author = {Rogers, F. J. and Nayfonov, A.},
  year = {2002},
  month = sep,
  volume = {576},
  pages = {1064--1074},
  issn = {0004-637X},
  doi = {10.1086/341894},
  abstract = {We are in the process of updating and extending the OPAL  equation-of-state (EOS) and opacity data to include low-mass stars. The EOS part of that effort now is complete, and the results are described herein. The new data cover main-sequence stars having mass {$>$}=0.1 Msolar. As a result of the more extreme matter conditions encountered with low-mass stars, we have added new physics. The electrons are now treated as relativistic, and we have improved our treatment of molecules. We also consider the implications of the new results for helioseismology.},
  journal = {ApJ},
  keywords = {Atomic Processes,Equation of State,Sun: Oscillations}
}

@article{Rogers2015,
  title = {Most 1.6 {{Earth}}-Radius {{Planets}} Are {{Not Rocky}}},
  author = {Rogers, Leslie A.},
  year = {2015},
  month = mar,
  volume = {801},
  pages = {41},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/801/1/41},
  abstract = {The Kepler mission, combined with ground-based radial velocity (RV) follow-up and dynamical analyses of transit timing variations, has revolutionized the observational constraints on sub-Neptune-sized planet compositions. The results of an extensive Kepler follow-up program including multiple Doppler measurements for 22 planet-hosting stars more than doubles the population of sub-Neptune-sized transiting planets that have RV mass constraints. This unprecedentedly large and homogeneous sample of planets with both mass and radius constraints opens the possibility of a statistical study of the underlying population of planet compositions. We focus on the intriguing transition between rocky exoplanets (comprised of iron and silicates) and planets with voluminous layers of volatiles (H/He and astrophysical ices). Applying a hierarchical Bayesian statistical approach to the sample of Kepler transiting sub-Neptune planets with Keck RV follow-up, we constrain the fraction of close-in planets (with orbital periods less than {$\sim$}50 days) that are sufficiently dense to be rocky, as a function of planet radius. We show that the majority of 1.6 \{\{R\}\textbackslash oplus \} planets have too low density to be comprised of Fe and silicates alone. At larger radii, the constraints on the fraction of rocky planets are even more stringent. These insights into the size demographics of rocky and volatile-rich planets offer empirical constraints to planet formation theories, and guide the range of planet radii to be considered in studies of the occurrence rate of ``Earth-like'' planets, \{\{{$\eta$} \}\textbackslash oplus \}.},
  journal = {ApJ},
  keywords = {methods: data analysis,methods: statistical,planetary systems,planets and satellites: composition,techniques: photometric,techniques: radial velocities}
}

@article{Roxburgh2004,
  title = {2-Dimensional Models of Rapidly Rotating Stars {{I}}. {{Uniformly}} Rotating Zero Age Main Sequence Stars},
  author = {Roxburgh, I. W.},
  year = {2004},
  month = dec,
  volume = {428},
  pages = {171--179},
  issn = {0004-6361},
  doi = {10.1051/0004-6361:20041202},
  abstract = {We present results for 2-dimensional models of rapidly rotating main  sequence stars for the case where the angular velocity {$\Omega$} is constant throughout the star. The algorithm used solves for the structure on equipotential surfaces and iteratively updates the total potential, solving Poisson's equation by Legendre polynomial decomposition; the algorithm can readily be extended to include rotation constant on cylinders. We show that this only requires a small number of Legendre polynomials to accurately represent the solution. We present results for models of homogeneous zero age main sequence stars of mass 1, 2, 5, 10 M{$\odot$} with a range of angular velocities up to break up. The models have a composition X=0.70, Z=0.02 and were computed using the OPAL equation of state and OPAL/Alexander opacities, and a mixing length model of convection modified to include the effect of rotation. The models all show a decrease in luminosity L and polar radius Rp with increasing angular velocity, the magnitude of the decrease varying with mass but of the order of a few percent for rapid rotation, and an increase in equatorial radius Re. Due to the contribution of the gravitational multipole moments the parameter {$\Omega$}2 Re3/GM can exceed unity in very rapidly rotating stars and Re/Rp can exceed 1.5.},
  journal = {A\&A},
  keywords = {stars: interiors,stars: rotation}
}

@article{Ruder2016,
  ids = {Ruder2016a},
  title = {An Overview of Gradient Descent Optimization Algorithms},
  author = {Ruder, Sebastian},
  year = {2016},
  month = sep,
  abstract = {Gradient descent optimization algorithms, while increasingly popular, are often used as black-box optimizers, as practical explanations of their strengths and weaknesses are hard to come by. This article aims to provide the reader with intuitions with regard to the behaviour of different algorithms that will allow her to put them to use. In the course of this overview, we look at different variants of gradient descent, summarize challenges, introduce the most common optimization algorithms, review architectures in a parallel and distributed setting, and investigate additional strategies for optimizing gradient descent.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:1609.04747},
  eprint = {1609.04747},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Computer Science - Machine Learning},
  primaryclass = {cs.LG}
}

@article{Rumelhart.Hinton.ea1986,
  title = {Learning Representations by Back-Propagating Errors},
  author = {Rumelhart, David E. and Hinton, Geoffrey E. and Williams, Ronald J.},
  year = {1986},
  month = oct,
  volume = {323},
  pages = {533--536},
  publisher = {{Nature Publishing Group}},
  issn = {1476-4687},
  doi = {10.1038/323533a0},
  abstract = {We describe a new learning procedure, back-propagation, for networks of neurone-like units. The procedure repeatedly adjusts the weights of the connections in the network so as to minimize a measure of the difference between the actual output vector of the net and the desired output vector. As a result of the weight adjustments, internal `hidden' units which are not part of the input or output come to represent important features of the task domain, and the regularities in the task are captured by the interactions of these units. The ability to create useful new features distinguishes back-propagation from earlier, simpler methods such as the perceptron-convergence procedure1.},
  copyright = {1986 Nature Publishing Group},
  journal = {Nature},
  language = {en},
  number = {6088}
}

@article{Salvatier.Wiecki.ea2016,
  title = {Probabilistic Programming in {{Python}} Using {{PyMC3}}},
  author = {Salvatier, John and Wiecki, Thomas V. and Fonnesbeck, Christopher},
  year = {2016},
  month = apr,
  volume = {2},
  pages = {e55},
  publisher = {{PeerJ Inc.}},
  issn = {2376-5992},
  doi = {10.7717/peerj-cs.55},
  abstract = {Probabilistic programming allows for automatic Bayesian inference on user-defined probabilistic models. Recent advances in Markov chain Monte Carlo (MCMC) sampling allow inference on increasingly complex models. This class of MCMC, known as Hamiltonian Monte Carlo, requires gradient information which is often not readily available. PyMC3 is a new open source probabilistic programming framework written in Python that uses Theano to compute gradients via automatic differentiation as well as compile probabilistic programs on-the-fly to C for increased speed. Contrary to other probabilistic programming languages, PyMC3 allows model specification directly in Python code. The lack of a domain specific language allows for great flexibility and direct interaction with the model. This paper is a tutorial-style introduction to this software package.},
  journal = {PeerJ Comput. Sci.},
  keywords = {python,statistical analysis},
  language = {en}
}

@article{Sandquist.Stello.ea2020,
  title = {Variability in the {{Massive Open Cluster NGC}} 1817 from {{K2}}: {{A Rich Population}} of {{Asteroseismic Red Clump}}, {{Eclipsing Binary}}, and {{Main}}-Sequence {{Pulsating Stars}}},
  shorttitle = {Variability in the {{Massive Open Cluster NGC}} 1817 from {{K2}}},
  author = {Sandquist, Eric L. and Stello, Dennis and Arentoft, Torben and Brogaard, Karsten and Grundahl, Frank and Vanderburg, Andrew and Hedlund, Anne and DeWitt, Ryan and Ackerman, Taylor R. and Aguilar, Miguel and Buckner, Andrew J. and Juarez, Christian and Ortiz, Arturo J. and Richarte, David and Rivera, Daniel I. and Schlapfer, Levi},
  year = {2020},
  month = mar,
  volume = {159},
  pages = {96},
  issn = {0004-6256},
  doi = {10.3847/1538-3881/ab68df},
  abstract = {We present a survey of variable stars detected in K2 Campaign 13 within  the massive intermediate-age ({$\sim$}1 Gyr) open cluster NGC 1817. We identify a complete sample of 44 red clump stars in the cluster, and have measured asteroseismic quantities ({$\nu$}max and/or {$\Delta\nu$}) for 29 of them. Five stars showed suppressed dipole modes, and the occurrence rates indicate that mode suppression is unaffected by evolution through core helium burning. A subset of the giants in NGC 1817 (and in the similarly aged cluster NGC 6811) have {$\nu$}max and {$\Delta\nu$} values at or near the maximum observed for core helium-burning stars, indicating they have core masses near the minimum for fully nondegenerate helium ignition. Further asteroseismic study of these stars can constrain the minimum helium core mass in red clump stars and the physics that determines this limit. Two giant stars show photometric variations on timescales similar to previously measured spectroscopic orbits. Thirteen systems in the field show eclipses, but only five are probable cluster members. We identify 32 {$\delta$} Sct pulsators, 27 {$\gamma$} Dor candidates, and 7 hybrids that are probable cluster members, with most being new detections. We used the ensemble properties of the {$\delta$} Sct stars to identify stars with possible radial pulsation modes. Among the oddities we have uncovered are: an eccentric orbit for a short-period binary containing a {$\delta$} Sct pulsating star; a rare subgiant within the Hertzsprung gap showing {$\delta$} Sct pulsations; and two hot {$\gamma$} Dor pulsating star candidates.},
  journal = {The Astronomical Journal},
  keywords = {1160,1557,1595,1599,2050,444,73}
}

@article{Scargle1982,
  title = {Studies in Astronomical Time Series Analysis. {{II}} - {{Statistical}} Aspects of Spectral Analysis of Unevenly Spaced Data},
  author = {Scargle, J. D.},
  year = {1982},
  month = dec,
  volume = {263},
  pages = {835--853},
  issn = {0004-637X},
  doi = {10.1086/160554},
  abstract = {Detection of a periodic signal hidden in noise is frequently a goal in  astronomical data analysis. This paper does not introduce a new detection technique, but instead studies the reliability and efficiency of detection with the most commonly used technique, the periodogram, in the case where the observation times are unevenly spaced. This choice was made because, of the methods in current use, it appears to have the simplest statistical behavior. A modification of the classical definition of the periodogram is necessary in order to retain the simple statistical behavior of the evenly spaced case. With this modification, periodogram analysis and least-squares fitting of sine waves to the data are exactly equivalent. Certain difficulties with the use of the periodogram are less important than commonly believed in the case of detection of strictly periodic signals. In addition, the standard method for mitigating these difficulties (tapering) can be used just as well if the sampling is uneven. An analysis of the statistical significance of signal detections is presented, with examples},
  journal = {ApJ},
  keywords = {Astronomy,Fourier Transformation,Frequency Response,Power Spectra,Signal Detection,Signal To Noise Ratios,Spectrum Analysis,Statistical Distributions,Time Series Analysis}
}

@article{Scott.Grevesse.ea2015,
  title = {The Elemental Composition of the {{Sun}}. {{I}}. {{The}} Intermediate Mass Elements {{Na}} to {{Ca}}},
  author = {Scott, Pat and Grevesse, Nicolas and Asplund, Martin and Sauval, A. Jacques and Lind, Karin and Takeda, Yoichi and Collet, Remo and Trampedach, Regner and Hayek, Wolfgang},
  year = {2015},
  month = jan,
  volume = {573},
  pages = {A25},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201424109},
  abstract = {The chemical composition of the Sun is an essential piece of reference  data for astronomy, cosmology, astroparticle, space and geo-physics: elemental abundances of essentially all astronomical objects are referenced to the solar composition, and basically every process involving the Sun depends on its composition. This article, dealing with the intermediate-mass elements Na to Ca, is the first in a series describing the comprehensive re-determination of the solar composition. In this series we severely scrutinise all ingredients of the analysis across all elements, to obtain the most accurate, homogeneous and reliable results possible. We employ a highly realistic 3D hydrodynamic model of the solar photosphere, which has successfully passed an arsenal of observational diagnostics. For comparison, and to quantify remaining systematic errors, we repeat the analysis using three different 1D hydrostatic model atmospheres (marcs, miss and Holweger \& M\"uller 1974, Sol. Phys., 39, 19) and a horizontally and temporally-averaged version of the 3D model ({$\langle$} 3D {$\rangle$}). We account for departures from local thermodynamic equilibrium (LTE) wherever possible. We have scoured the literature for the best possible input data, carefully assessing transition probabilities, hyperfine splitting, partition functions and other data for inclusion in the analysis. We have put the lines we use through a very stringent quality check in terms of their observed profiles and atomic data, and discarded all that we suspect to be blended. Our final recommended 3D+NLTE abundances are: log {$\varepsilon$}Na = 6.21 {$\pm$} 0.04, log {$\varepsilon$}Mg = 7.59 {$\pm$} 0.04, log {$\varepsilon$}Al = 6.43 {$\pm$} 0.04, log {$\varepsilon$}Si = 7.51 {$\pm$} 0.03, log {$\varepsilon$}P = 5.41 {$\pm$} 0.03, log {$\varepsilon$}S = 7.13 {$\pm$} 0.03, log {$\varepsilon$}K = 5.04 {$\pm$} 0.05 and log {$\varepsilon$}Ca = 6.32 {$\pm$} 0.03. The uncertainties include both statistical and systematic errors. Our results are systematically smaller than most previous ones with the 1D semi-empirical Holweger \& M\"uller model, whereas the {$\langle$} 3D {$\rangle$} model returns abundances very similar to the full 3D calculations. This analysis provides a complete description and a slight update of the results presented in Asplund et al. (2009, ARA\&A, 47, 481) for Na to Ca, and includes full details of all lines and input data used. Tables 1-4 and Appendix A are available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {convection,formation,line:,line: profiles,Sun: abundances,Sun: granulation,Sun: photosphere}
}

@article{Serenelli.Basu.ea2009,
  title = {New {{Solar Composition}}: {{The Problem}} with {{Solar Models Revisited}}},
  shorttitle = {New {{Solar Composition}}},
  author = {Serenelli, Aldo M. and Basu, Sarbani and Ferguson, Jason W. and Asplund, Martin},
  year = {2009},
  month = nov,
  volume = {705},
  pages = {L123-L127},
  doi = {10.1088/0004-637X/705/2/L123},
  abstract = {We construct updated solar models with different sets of solar abundances, including the most recent determinations by Asplund et al. The latter work predicts a larger (\textasciitilde 10\%) solar metallicity compared to previous measurements by the same authors but significantly lower (\textasciitilde 25\%) than the recommended value from a decade ago by Grevesse \& Sauval. We compare the results of our models with determinations of the solar structure inferred through helioseismology measurements. The model that uses the most recent solar abundance determinations predicts the base of the solar convective envelope to be located at R CZ = 0.724 R sun and a surface helium mass fraction of Y surf = 0.231. These results are in conflict with helioseismology data (R CZ = 0.713 {$\pm$} 0.001 R sun and Y surf = 0.2485 {$\pm$} 0.0035) at 5{$\sigma$} and 11{$\sigma$} levels, respectively. Using the new solar abundances, we calculate the magnitude by which radiative opacities should be modified in order to restore agreement with helioseismology. We find that a maximum change of \textasciitilde 15\% at the base of the convective zone is required with a smooth decrease toward the core, where the change needed is \textasciitilde 5\%. The required change at the base of the convective envelope is about half the value estimated previously. We also present the solar neutrino fluxes predicted by the new models. The most important changes brought about by the new solar abundances are the increase by \textasciitilde 10\% in the predicted 13N and 15O fluxes that arise mostly due to the increase in the C and N abundances in the newly determined solar composition.},
  journal = {Astrophys. J. Lett.},
  keywords = {neutrinos,Sun: abundances,Sun: helioseismology,Sun: interior}
}

@article{Serenelli.Basu2010,
  title = {Determining the {{Initial Helium Abundance}} of the {{Sun}}},
  author = {Serenelli, Aldo M. and Basu, Sarbani},
  year = {2010},
  month = aug,
  volume = {719},
  pages = {865--872},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/719/1/865},
  abstract = {We determine the dependence of the initial helium abundance and the present-day helium abundance in the convective envelope of solar models (Y ini and Y surf, respectively) on the parameters that are used to construct the models. We do so by using reference standard solar models (SSMs) to compute the power-law coefficients of the dependence of Y ini and Y surf on the input parameters. We use these dependencies to determine the correlation between Y ini and Y surf and use this correlation to eliminate uncertainties in Y ini from all solar model input parameters except the microscopic diffusion rate. We find an expression for Y ini that depends only on Y surf and the diffusion rate. By adopting the helioseismic determination of solar surface helium abundance, Y surf sun = 0.2485 {$\pm$} 0.0035, and an uncertainty of 20\% for the diffusion rate, we find that the initial solar helium abundance, Y ini sun, is 0.278 {$\pm$} 0.006 independently of the reference SSMs (and particularly on the adopted solar abundances) used in the derivation of the correlation between Y ini and Y surf. When non-SSMs with extra mixing are used, then we derive Y ini sun = 0.273 {$\pm$} 0.006. In both cases, the derived Y ini sun value is higher than that directly derived from solar model calibrations when the low-metallicity solar abundances (e.g., by Asplund et al.) are adopted in the models.},
  journal = {ApJ},
  keywords = {diffusion,Sun: abundances,Sun: helioseismology,Sun: interior}
}

@article{Serenelli.Johnson.ea2017,
  title = {The {{First APOKASC Catalog}} of {{Kepler Dwarf}} and {{Subgiant Stars}}},
  author = {Serenelli, Aldo and Johnson, Jennifer and Huber, Daniel and Pinsonneault, Marc and Ball, Warrick H. and Tayar, Jamie and Silva Aguirre, Victor and Basu, Sarbani and Troup, Nicholas and Hekker, Saskia and Kallinger, Thomas and Stello, Dennis and Davies, Guy R. and Lund, Mikkel N. and Mathur, Savita and Mosser, Benoit and Stassun, Keivan G. and Chaplin, William J. and Elsworth, Yvonne and Garc{\'i}a, Rafael A. and Handberg, Rasmus and Holtzman, Jon and Hearty, Fred and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Gaulme, Patrick and Zamora, Olga},
  year = {2017},
  month = dec,
  volume = {233},
  pages = {23},
  issn = {0067-0049},
  doi = {10.3847/1538-4365/aa97df},
  abstract = {We present the first APOKASC catalog of spectroscopic and asteroseismic data for dwarfs and subgiants. Asteroseismic data for our sample of 415 objects have been obtained by the Kepler mission in short (58.5 s) cadence, and light curves span from 30 up to more than 1000 days. The spectroscopic parameters are based on spectra taken as part of the Apache Point Observatory Galactic Evolution Experiment and correspond to Data Release 13 of the Sloan Digital Sky Survey. We analyze our data using two independent \{T\}\{eff\} scales, the spectroscopic values from DR13 and those derived from SDSS griz photometry. We use the differences in our results arising from these choices as a test of systematic temperature uncertainties and find that they can lead to significant differences in the derived stellar properties. Determinations of surface gravity (\{log\}g), mean density ({$<$} {$\rho$} {$>$} ), radius (R), mass (M), and age ({$\tau$}) for the whole sample have been carried out by means of (stellar) grid-based modeling. We have thoroughly assessed random and systematic error sources in the spectroscopic and asteroseismic data, as well as in the grid-based modeling determination of the stellar quantities provided in the catalog. We provide stellar properties determined for each of the two \{T\}\{eff\} scales. The median combined (random and systematic) uncertainties are 2\% (0.01 dex; \{log\}g), 3.4\% ({$<$} {$\rho$} {$>$} ), 2.6\% (R), 5.1\% (M), and 19\% ({$\tau$}) for the photometric \{T\}\{eff\} scale and 2\% (\{log\}g), 3.5\% ({$<$} {$\rho$} {$>$} ), 2.7\% (R), 6.3\% (M), and 23\% ({$\tau$}) for the spectroscopic scale. We present comparisons with stellar quantities in the asteroseismic catalog by Chaplin et al. that highlight the importance of having metallicity measurements for determining stellar parameters accurately. Finally, we compare our results with those coming from a variety of sources, including stellar radii determined from TGAS parallaxes and asteroseismic analyses based on individual frequencies. We find a very good agreement for all inferred quantities. The latter comparison, in particular, gives strong support to the determination of stellar quantities based on global seismology, a relevant result for future missions such as TESS and PLATO.},
  journal = {ApJS},
  keywords = {asteroseismology,catalogs,dwarfs,Kepler,stars: fundamental parameters,subgiants,surveys}
}

@article{Si.vanDyk.ea2017,
  ids = {Si.vanDyk.ea2017a},
  title = {A Hierarchical Model for the Ages of {{Galactic}} Halo White Dwarfs},
  author = {Si, Shijing and {van Dyk}, David A. and {von Hippel}, Ted and Robinson, Elliot and Webster, Aaron and Stenning, David},
  year = {2017},
  month = jul,
  volume = {468},
  pages = {4374--4388},
  issn = {0035-8711},
  doi = {10.1093/mnras/stx765},
  abstract = {In astrophysics, we often aim to estimate one or more parameters for each member object in a population and study the distribution of the fitted parameters across the population. In this paper, we develop novel methods that allow us to take advantage of existing software designed for such case-by-case analyses to simultaneously fit parameters of both the individual objects and the parameters that quantify their distribution across the population. Our methods are based on Bayesian hierarchical modelling that is known to produce parameter estimators for the individual objects that are on average closer to their true values than estimators based on case-by-case analyses. We verify this in the context of estimating ages of Galactic halo white dwarfs (WDs) via a series of simulation studies. Finally, we deploy our new techniques on optical and near-infrared photometry of 10 candidate halo WDs to obtain estimates of their ages along with an estimate of the mean age of Galactic halo WDs of 12.11\_\{-0.86\}\^\{+0.85\} Gyr. Although this sample is small, our technique lays the ground work for large-scale studies using data from the Gaia mission.},
  journal = {MNRAS},
  keywords = {Galaxy: halo,methods: statistical,white dwarfs}
}

@article{SilvaAguirre.Davies.ea2015,
  title = {Ages and Fundamental Properties of {{Kepler}} Exoplanet Host Stars from Asteroseismology},
  author = {Silva Aguirre, V. and Davies, G. R. and Basu, S. and {Christensen-Dalsgaard}, J. and Creevey, O. and Metcalfe, T. S. and Bedding, T. R. and Casagrande, L. and Handberg, R. and Lund, M. N. and Nissen, P. E. and Chaplin, W. J. and Huber, D. and Serenelli, A. M. and Stello, D. and Van Eylen, V. and Campante, T. L. and Elsworth, Y. and Gilliland, R. L. and Hekker, S. and Karoff, C. and Kawaler, S. D. and Kjeldsen, H. and Lundkvist, M. S.},
  year = {2015},
  month = sep,
  volume = {452},
  pages = {2127},
  doi = {10.1093/mnras/stv1388},
  abstract = {We present a study of 33 Kepler planet-candidate host stars for which asteroseismic observations have sufficiently high signal-to-noise ratio to allow extraction of individual pulsation frequencies. We implement a new Bayesian scheme that is flexible in its input to process individual oscillation frequencies, combinations of them, and average asteroseismic parameters, and derive robust fundamental properties for these targets. Applying this scheme to grids of evolutionary models yields stellar properties with median statistical uncertainties of 1.2 per cent (radius), 1.7 per cent (density), 3.3 per cent (mass), 4.4 per cent (distance), and 14 per cent (age), making this the exoplanet host-star sample with the most precise and uniformly determined fundamental parameters to date. We assess the systematics from changes in the solar abundances and mixing-length parameter, showing that they are smaller than the statistical errors. We also determine the stellar properties with three other fitting algorithms and explore the systematics arising from using different evolution and pulsation codes, resulting in 1 per cent in density and radius, and 2 per cent and 7 per cent in mass and age, respectively. We confirm previous findings of the initial helium abundance being a source of systematics comparable to our statistical uncertainties, and discuss future prospects for constraining this parameter by combining asteroseismology and data from space missions. Finally, we compare our derived properties with those obtained using the global average asteroseismic observables along with effective temperature and metallicity, finding excellent level of agreement. Owing to selection effects, our results show that the majority of the high signal-to-noise ratio asteroseismic Kepler host stars are older than the Sun.},
  journal = {MNRAS},
  keywords = {asteroseismology,exoplanets,stellar ages},
  language = {en},
  number = {2}
}

@article{SilvaAguirre.Lund.ea2017,
  title = {Standing on the {{Shoulders}} of {{Dwarfs}}: The {{Kepler Asteroseismic LEGACY Sample}}. {{II}}.{{Radii}}, {{Masses}}, and {{Ages}}},
  shorttitle = {Standing on the {{Shoulders}} of {{Dwarfs}}},
  author = {Silva Aguirre, V{\'i}ctor and Lund, Mikkel N. and Antia, H. M. and Ball, Warrick H. and Basu, Sarbani and {Christensen-Dalsgaard}, J{\o}rgen and Lebreton, Yveline and Reese, Daniel R. and Verma, Kuldeep and Casagrande, Luca and Justesen, Anders B. and Mosumgaard, Jakob R. and Chaplin, William J. and Bedding, Timothy R. and Davies, Guy R. and Handberg, Rasmus and Houdek, G{\"u}nter and Huber, Daniel and Kjeldsen, Hans and Latham, David W. and White, Timothy R. and Coelho, Hugo R. and Miglio, Andrea and Rendle, Ben},
  year = {2017},
  month = feb,
  volume = {835},
  pages = {173},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/835/2/173},
  abstract = {We use asteroseismic data from the Kepler satellite to determine  fundamental stellar properties of the 66 main-sequence targets observed for at least one full year by the mission. We distributed tens of individual oscillation frequencies extracted from the time series of each star among seven modeling teams who applied different methods to determine radii, masses, and ages for all stars in the sample. Comparisons among the different results reveal a good level of agreement in all stellar properties, which is remarkable considering the variety of codes, input physics, and analysis methods employed by the different teams. Average uncertainties are of the order of \texttildelow 2\% in radius, \texttildelow 4\% in mass, and \texttildelow 10\% in age, making this the best-characterized sample of main-sequence stars available to date. Our predicted initial abundances and mixing-length parameters are checked against inferences from chemical enrichment laws {$\Delta$}Y/{$\Delta$}Z and predictions from 3D atmospheric simulations. We test the accuracy of the determined stellar properties by comparing them to the Sun, angular diameter measurements, Gaia parallaxes, and binary evolution, finding excellent agreement in all cases and further confirming the robustness of asteroseismically determined physical parameters of stars when individual frequencies of oscillation are available. Baptised as the Kepler dwarfs LEGACY sample, these stars are the solar-like oscillators with the best asteroseismic properties available for at least another decade. All data used in this analysis and the resulting stellar parameters are made publicly available for the community.},
  journal = {ApJ},
  keywords = {asteroseismology,dwarfs,mixing-length theory,stars: fundamental parameters,stars: oscillations,stellar ages,stellar masses}
}

@article{Skrutskie.Cutri.ea2006,
  title = {The {{Two Micron All Sky Survey}} ({{2MASS}})},
  author = {Skrutskie, M. F. and Cutri, R. M. and Stiening, R. and Weinberg, M. D. and Schneider, S. and Carpenter, J. M. and Beichman, C. and Capps, R. and Chester, T. and Elias, J. and Huchra, J. and Liebert, J. and Lonsdale, C. and Monet, D. G. and Price, S. and Seitzer, P. and Jarrett, T. and Kirkpatrick, J. D. and Gizis, J. E. and Howard, E. and Evans, T. and Fowler, J. and Fullmer, L. and Hurt, R. and Light, R. and Kopan, E. L. and Marsh, K. A. and McCallon, H. L. and Tam, R. and Van Dyk, S. and Wheelock, S.},
  year = {2006},
  month = feb,
  volume = {131},
  pages = {1163--1183},
  doi = {10.1086/498708},
  abstract = {Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998\% of the celestial sphere in the near-infrared J (1.25 {$\mu$}m), H (1.65 {$\mu$}m), and Ks (2.16 {$\mu$}m) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 7.8 s of integration time accumulated for each point on the sky and strict quality control yielded a 10 {$\sigma$} point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and Ks bands, respectively, for virtually the entire sky. Bright source extractions have 1 {$\sigma$} photometric uncertainty of {$<$}0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are {$<$}0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.},
  journal = {AJ},
  keywords = {Catalogs,Infrared: General,Surveys}
}

@article{Smith.Stumpe.ea2012,
  title = {Kepler {{Presearch Data Conditioning II}} - {{A Bayesian Approach}} to {{Systematic Error Correction}}},
  author = {Smith, Jeffrey C. and Stumpe, Martin C. and Van Cleve, Jeffrey E. and Jenkins, Jon M. and Barclay, Thomas S. and Fanelli, Michael N. and Girouard, Forrest R. and Kolodziejczak, Jeffery J. and McCauliff, Sean D. and Morris, Robert L. and Twicken, Joseph D.},
  year = {2012},
  month = sep,
  volume = {124},
  pages = {1000},
  issn = {0004-6280},
  doi = {10.1086/667697},
  abstract = {With the unprecedented photometric precision of the Kepler spacecraft,  significant systematic and stochastic errors on transit signal levels are observable in the Kepler photometric data. These errors, which include discontinuities, outliers, systematic trends, and other instrumental signatures, obscure astrophysical signals. The presearch data conditioning (PDC) module of the Kepler data analysis pipeline tries to remove these errors while preserving planet transits and other astrophysically interesting signals. The completely new noise and stellar variability regime observed in Kepler data poses a significant problem to standard cotrending methods. Variable stars are often of particular astrophysical interest, so the preservation of their signals is of significant importance to the astrophysical community. We present a Bayesian maximum a posteriori (MAP) approach, where a subset of highly correlated and quiet stars is used to generate a cotrending basis vector set, which is in turn used to establish a range of ``reasonable'' robust fit parameters. These robust fit parameters are then used to generate a Bayesian prior and a Bayesian posterior probability distribution function (PDF) which, when maximized, finds the best fit that simultaneously removes systematic effects while reducing the signal distortion and noise injection that commonly afflicts simple least-squares (LS) fitting. A numerical and empirical approach is taken where the Bayesian prior PDFs are generated from fits to the light-curve distributions themselves.},
  journal = {PASP}
}

@article{Soderblom2010,
  title = {The {{Ages}} of {{Stars}}},
  author = {Soderblom, David R.},
  year = {2010},
  month = aug,
  volume = {48},
  pages = {581--629},
  issn = {0066-4146, 1545-4282},
  doi = {10.1146/annurev-astro-081309-130806},
  abstract = {The age of an individual star cannot be measured, only estimated through mostly model-dependent or empirical methods, and no single method works well for a broad range of stellar types or for a full range in age. This review presents a summary of the available techniques for age-dating stars and ensembles of stars, their realms of applicability, and their strengths and weaknesses. My emphasis is on low-mass stars because they are present from all epochs of star formation in the Galaxy and because they present both special opportunities and problems. The ages of open clusters are important for understanding the limitations of stellar models and for calibrating empirical age indicators. For individual stars, a hierarchy of quality for the available age-dating methods is described. Although our present ability to determine the ages of even the nearest stars is mediocre, the next few years hold great promise as asteroseismology probes beyond stellar surfaces and starts to provide precise interior properties of stars and as models continue to improve when stressed by better observations.},
  journal = {ARA\&A},
  keywords = {stellar ages},
  language = {en},
  number = {1}
}

@article{Sonoi.Samadi.ea2015,
  title = {Surface-Effect Corrections for Solar-like Oscillations Using {{3D}} Hydrodynamical Simulations. {{I}}. {{Adiabatic}} Oscillations},
  author = {Sonoi, T. and Samadi, R. and Belkacem, K. and Ludwig, H.-G. and Caffau, E. and Mosser, B.},
  year = {2015},
  month = nov,
  volume = {583},
  pages = {A112},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201526838},
  abstract = {Context. The CoRoT and Kepler space-borne missions have provided us with  a wealth of high-quality observational data that allows for seismic inferences of stellar interiors. This requires the computation of precise and accurate theoretical frequencies, but imperfect modeling of the uppermost stellar layers introduces systematic errors. To overcome this problem, an empirical correction has been introduced by Kjeldsen et al. (2008, ApJ, 683, L175) and is now commonly used for seismic inferences. Nevertheless, we still lack a physical justification allowing for the quantification of the surface-effect corrections. Aims: Our aim is to constrain the surface-effect corrections across the Hertzsprung-Russell (HR) diagram using a set of 3D hydrodynamical simulations. Methods: We used a grid of these simulations computed with the CO5BOLD code to model the outer layers of solar-like stars. Upper layers of the corresponding 1D standard models were then replaced by the layers obtained from the horizontally averaged 3D models. The frequency differences between these patched models and the 1D standard models were then calculated using the adiabatic approximation and allowed us to constrain the Kjeldsen et al. power law, as well as a Lorentzian formulation. Results: We find that the surface effects on modal frequencies depend significantly on both the effective temperature and the surface gravity. We further provide the variation in the parameters related to the surface-effect corrections using their power law as well as a Lorentzian formulation. Scaling relations between these parameters and the elevation (related to the Mach number) is also provided. The Lorentzian formulation is shown to be more robust for the whole frequency spectrum, while the power law is not suitable for the frequency shifts in the frequency range above {$\nu$}max. Finally, we show that, owing to turbulent pressure, the elevation of the uppermost layers modifies the location of the hydrogen ionization zone and consequently introduces glitches in the surface effects for models with high (low) effective temperature (surface gravity).  Conclusions: Surface-effect corrections vary significantly across the HR diagram. Therefore, empirical relations like those by Kjeldsen et al. must not be calibrated on the Sun but should instead be constrained using realistic physical modeling as provided by 3D hydrodynamical simulations.},
  journal = {A\&A},
  keywords = {asteroseismology,convection,stars: atmospheres,stars: low-mass,stars: oscillations,stars: solar-type}
}

@article{Stancliffe.Fossati.ea2016,
  title = {Confronting Uncertainties in Stellar Physics. {{II}}. {{Exploring}} Differences in Main-Sequence Stellar Evolution Tracks},
  author = {Stancliffe, R. J. and Fossati, L. and Passy, J.-C. and Schneider, F. R. N.},
  year = {2016},
  month = feb,
  volume = {586},
  pages = {A119},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201527099},
  abstract = {We assess the systematic uncertainties in stellar evolutionary  calculations for low- to intermediate-mass, main-sequence stars. We compare published stellar tracks from several different evolution codes with our own tracks computed using the stellar codes stars and mesa. In particular, we focus on tracks of 1 and 3 M{$\odot$} at solar metallicity. We find that the spread in the available 1 M{$\odot$} tracks (computed before the recent solar composition revision) can be covered by tracks between 0.97-1.01 M{$\odot$} computed with the stars code. We assess some possible causes of the origin of this uncertainty, including how the choice of input physics and the solar constraints used to perform the solar calibration affect the tracks. We find that for a 1 M{$\odot$} track, uncertainties of around 10\% in the initial hydrogen abundance and initial metallicity produce around a 2\% error in mass. For the 3 M{$\odot$} tracks, there is very little difference between the tracks from the various different stellar codes. The main difference comes in the extent of the main sequence, which we believe results from the different choices of the implementation of convective overshooting in the core. Uncertainties in the initial abundances lead to a 1-2\% error in the mass determination. These uncertainties cover only part of the total error budget, which should also include uncertainties in the input physics (e.g., reaction rates, opacities, convective models) and any missing physics (e.g., radiative levitation, rotation, magnetic fields). Uncertainties in stellar surface properties such as luminosity and effective temperature will further reduce the accuracy of any potential mass determinations.},
  journal = {A\&A},
  keywords = {stars: evolution,stars: interiors,stars: low-mass}
}

@article{Stumpe.Smith.ea2012,
  title = {Kepler {{Presearch Data Conditioning I}}\textemdash{{Architecture}} and {{Algorithms}} for {{Error Correction}} in {{Kepler Light Curves}}},
  author = {Stumpe, Martin C. and Smith, Jeffrey C. and Van Cleve, Jeffrey E. and Twicken, Joseph D. and Barclay, Thomas S. and Fanelli, Michael N. and Girouard, Forrest R. and Jenkins, Jon M. and Kolodziejczak, Jeffery J. and McCauliff, Sean D. and Morris, Robert L.},
  year = {2012},
  month = sep,
  volume = {124},
  pages = {985},
  issn = {0004-6280},
  doi = {10.1086/667698},
  abstract = {Kepler provides light curves of 156,000 stars with unprecedented  precision. However, the raw data as they come from the spacecraft contain significant systematic and stochastic errors. These errors, which include discontinuities, systematic trends, and outliers, obscure the astrophysical signals in the light curves. To correct these errors is the task of the Presearch Data Conditioning (PDC) module of the Kepler data analysis pipeline. The original version of PDC in Kepler did not meet the extremely high performance requirements for the detection of miniscule planet transits or highly accurate analysis of stellar activity and rotation. One particular deficiency was that astrophysical features were often removed as a side effect of the removal of errors. In this article we introduce the completely new and significantly improved version of PDC which was implemented in Kepler SOC version 8.0. This new PDC version, which utilizes a Bayesian approach for removal of systematics, reliably corrects errors in the light curves while at the same time preserving planet transits and other astrophysically interesting signals. We describe the architecture and the algorithms of this new PDC module, show typical errors encountered in Kepler data, and illustrate the corrections using real light curve examples.},
  journal = {PASP}
}

@inproceedings{Sutskever.Martens.ea2013,
  title = {On the Importance of Initialization and Momentum in Deep Learning},
  author = {Sutskever, Ilya and Martens, James and Dahl, George and Hinton, Geoffrey},
  editor = {Dasgupta, Sanjoy and McAllester, David},
  year = {2013},
  month = jun,
  volume = {28},
  pages = {1139--1147},
  publisher = {{PMLR}},
  address = {{Atlanta, Georgia, USA}},
  abstract = {Deep and recurrent neural networks (DNNs and RNNs respectively) are powerful models that were considered to be almost impossible to train using stochastic gradient descent with momentum. In this paper, we show that when stochastic gradient descent with momentum uses a well-designed random initialization and a particular type of slowly increasing schedule for the momentum parameter, it can train both DNNs and RNNs (on datasets with long-term dependencies) to levels of performance that were previously achievable only with Hessian-Free optimization. We find that both the initialization and the momentum are crucial since poorly initialized networks cannot be trained with momentum and well-initialized networks perform markedly worse when the momentum is absent or poorly tuned. Our success training these models suggests that previous attempts to train deep and recurrent neural networks from random initializations have likely failed due to poor initialization schemes. Furthermore, carefully tuned momentum methods suffice for dealing with the curvature issues in deep and recurrent network training objectives without the need for sophisticated second-order methods.},
  series = {Proceedings of Machine Learning Research}
}

@article{Tassoul1980,
  title = {Asymptotic Approximations for Stellar Nonradial Pulsations},
  author = {Tassoul, M.},
  year = {1980},
  month = aug,
  volume = {43},
  pages = {469--490},
  doi = {10.1086/190678},
  abstract = {The problem of linear nonradial oscillations in stars is reconsidered using sound asymptotic expansions. High-order p- and g-modes are investigated. In the case of g-modes, the possibility of resonance occurs when the model possesses more than one zone in which spatial oscillations may occur.},
  journal = {ApJS},
  keywords = {Asymptotic Methods,Mathematical Models,Stellar Models,Stellar Oscillations,Vibration Mode}
}

@article{Tayar.Claytor.ea2020,
  ids = {Tayar.Claytor.ea2020a},
  title = {A {{Guide}} to {{Realistic Uncertainties}} on {{Fundamental Properties}} of {{Solar}}-{{Type Exoplanet Host Stars}}},
  author = {Tayar, Jamie and Claytor, Zachary R. and Huber, Daniel and {van Saders}, Jennifer},
  year = {2020},
  month = dec,
  abstract = {Our understanding of the properties and demographics of exoplanets  critically relies on our ability to determine fundamental properties of their host stars. The advent of Gaia and large spectroscopic surveys has now made it in principle possible to infer properties of individual stars, including most exoplanet hosts, to very high precision. However, we show that in practice, such analyses are limited both by uncertainties in the fundamental scale, and by uncertainties in our models of stellar evolution, even for stars similar to the Sun. For example, we show that current uncertainties on measured interferometric angular diameters and bolometric fluxes set a systematic uncertainty floor of \$\textbackslash sim\$2\% in temperature, \$\textbackslash sim\$2\% in luminosity, and \$\textbackslash sim\$4\% in radius. Comparisons between widely available model grids suggest uncertainties of order \$\textbackslash sim\$5\% in mass and \$\textbackslash sim\$20\% in age for main sequence and subgiant stars. While the radius uncertainties are roughly constant over this range of stars, the model dependent uncertainties are a complex function of luminosity, temperature, and metallicity. We provide open-source software for approximating these uncertainties for individual targets, and discuss strategies for reducing these uncertainties in the future.},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System},
  archiveprefix = {arXiv},
  eid = {arXiv:2012.07957},
  eprint = {2012.07957},
  eprinttype = {arxiv},
  journal = {ArXiv e-prints},
  keywords = {Astrophysics - Earth and Planetary Astrophysics,Astrophysics - Solar and Stellar Astrophysics},
  primaryclass = {astro-ph.EP}
}

@article{Tayar.Somers.ea2017,
  title = {The {{Correlation}} between {{Mixing Length}} and {{Metallicity}} on the {{Giant Branch}}: {{Implications}} for {{Ages}} in the {{Gaia Era}}},
  shorttitle = {The {{Correlation}} between {{Mixing Length}} and {{Metallicity}} on the {{Giant Branch}}},
  author = {Tayar, Jamie and Somers, Garrett and Pinsonneault, Marc H. and Stello, Dennis and Mints, Alexey and Johnson, Jennifer A. and Zamora, O. and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Maraston, Claudia and Serenelli, Aldo and Allende Prieto, Carlos and Bastien, Fabienne A. and Basu, Sarbani and Bird, J. C. and Cohen, R. E. and Cunha, Katia and Elsworth, Yvonne and Garc{\'i}a, Rafael A. and Girardi, Leo and Hekker, Saskia and Holtzman, Jon and Huber, Daniel and Mathur, Savita and M{\'e}sz{\'a}ros, Szabolcs and Mosser, B. and Shetrone, Matthew and Silva Aguirre, Victor and Stassun, Keivan and Stringfellow, Guy S. and Zasowski, Gail and {Roman-Lopes}, A.},
  year = {2017},
  month = may,
  volume = {840},
  pages = {17},
  doi = {10.3847/1538-4357/aa6a1e},
  abstract = {In the updated APOGEE-Kepler catalog, we have asteroseismic and  spectroscopic data for over 3000 first ascent red giants. Given the size and accuracy of this sample, these data offer an unprecedented test of the accuracy of stellar models on the post-main-sequence. When we compare these data to theoretical predictions, we find a metallicity dependent temperature offset with a slope of around 100 K per dex in metallicity. We find that this effect is present in all model grids tested, and that theoretical uncertainties in the models, correlated spectroscopic errors, and shifts in the asteroseismic mass scale are insufficient to explain this effect. Stellar models can be brought into agreement with the data if a metallicity-dependent convective mixing length is used, with {$\Delta\alpha$} ML,YREC {$\sim$} 0.2 per dex in metallicity, a trend inconsistent with the predictions of three-dimensional stellar convection simulations. If this effect is not taken into account, isochrone ages for red giants from the Gaia data will be off by as much as a factor of two even at modest deviations from solar metallicity ([Fe/H] = -0.5).},
  journal = {ApJ},
  keywords = {stars: evolution,stars: fundamental parameters}
}

@article{Thoul.Bahcall.ea1994,
  title = {Element Diffusion in the Solar Interior},
  author = {Thoul, Anne A. and Bahcall, John N. and Loeb, Abraham},
  year = {1994},
  month = feb,
  volume = {421},
  pages = {828--842},
  doi = {10.1086/173695},
  abstract = {We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multicomponent fluid, including the residual heat-flow terms. No approximation is made concerning the relative concentrations, and no restriction is placed on the number of elements considered. We give improved diffusion velocities for hydrogen, helium, oxygen, and iron, in the analytic form derived previously by Bachall \& Loeb. These expressions for the diffusion velocities are simple to program in stellar evolution codes and are expected to be accurate to approximately 15\%. We find that the inclusion of the residual heat flow terms leads to an increase in the hydrogen diffusion velocity. We compare our numerical results with those obtained analytically by Bachall \& Loeb using a simplified treatment, as well as with those derived numerically by Michaud \& Proffitt. We find that for conditions characteristic of the Sun, the results of Bachall \& Loeb for the hydrogen diffusion velocity are smaller than our more accurate numerical results by approximately 30\%, except very near the center where the error becomes larger. The Michaud \& Proffitt results differ from the numerical results derived here by less than or = 15\%. Our complete treatment of element diffusion can be directly incorporated in a standard stellar evolution code by means of an exportable subroutine, but, for convenience, we also give simple analytical fits to our numerical results.},
  journal = {ApJ},
  keywords = {Abundance,Computerized Simulation,Diffusion,Flow Equations,Heavy Elements,Helium,Solar Interior,Stellar Composition,Stellar Evolution,Stellar Models,Subroutines}
}

@article{Townsend.Teitler2013,
  title = {{{GYRE}}: An Open-Source Stellar Oscillation Code Based on a New {{Magnus Multiple Shooting}} Scheme},
  shorttitle = {{{GYRE}}},
  author = {Townsend, R. H. D. and Teitler, S. A.},
  year = {2013},
  month = nov,
  volume = {435},
  pages = {3406--3418},
  issn = {0035-8711},
  doi = {10.1093/mnras/stt1533},
  abstract = {We present a new oscillation code, GYRE, which solves the stellar  pulsation equations (both adiabatic and non-adiabatic) using a novel Magnus Multiple Shooting numerical scheme devised to overcome certain weaknesses of the usual relaxation and shooting schemes appearing in the literature. The code is accurate (up to sixth-order in the number of grid points), robust, efficiently makes use of multiple processor cores and/or nodes and is freely available in source form for use and distribution. We verify the code against analytic solutions and results from other oscillation codes, in all cases finding good agreement. Then, we use the code to explore how the asteroseismic observables of a 1.5 M{$\odot$} star change as it evolves through the red-giant bump.},
  journal = {MNRAS},
  keywords = {methods: numerical,stars: evolution,stars: interiors,stars: oscillations,stars: variables: general}
}

@article{Trampedach.Stein.ea2014,
  title = {Improvements to Stellar Structure Models, Based on a Grid of {{3D}} Convection Simulations - {{II}}. {{Calibrating}} the Mixing-Length Formulation},
  author = {Trampedach, Regner and Stein, Robert F. and {Christensen-Dalsgaard}, J{\o}rgen and Nordlund, {\AA}ke and Asplund, Martin},
  year = {2014},
  month = dec,
  volume = {445},
  pages = {4366--4384},
  issn = {0035-8711},
  doi = {10.1093/mnras/stu2084},
  abstract = {We perform a calibration of the mixing length of convection in stellar  structure models against realistic 3D radiation-coupled hydrodynamics simulations of convection in stellar surface layers, determining the adiabat deep in convective stellar envelopes. The mixing-length parameter {$\alpha$} is calibrated by matching averages of the 3D simulations to 1D stellar envelope models, ensuring identical atomic physics in the two cases. This is done for a previously published grid of solar-metallicity convection simulations, covering from 4200 to 6900 K on the main sequence, and from 4300 to 5000 K for giants with log g = 2.2. Our calibration results in an {$\alpha$} varying from 1.6 for the warmest dwarf, which is just cool enough to admit a convective envelope, and up to 2.05 for the coolest dwarfs in our grid. In between these is a triangular plateau of {$\alpha$} {$\sim$} 1.76. The Sun is located on this plateau and has seen little change during its evolution so far. When stars ascend the giant branch, they largely do so along tracks of constant {$\alpha$}, with {$\alpha$} decreasing with increasing mass.},
  journal = {MNRAS},
  keywords = {convection,mixing-length theory,stars: atmospheres,stars: evolution,stellar convection}
}

@article{Ulrich1970,
  title = {The {{Five}}-{{Minute Oscillations}} on the {{Solar Surface}}},
  author = {Ulrich, Roger K.},
  year = {1970},
  month = dec,
  volume = {162},
  pages = {993},
  doi = {10.1086/150731},
  abstract = {Abstract image available at:  http://adsabs.harvard.edu/abs/1970ApJ...162..993U},
  journal = {ApJ}
}

@article{Ulrich1986,
  title = {Determination of Stellar Ages from Asteroseismology},
  author = {Ulrich, R. K.},
  year = {1986},
  month = jul,
  volume = {306},
  pages = {L37-L40},
  doi = {10.1086/184700},
  abstract = {This Letter shows that measurements of the stellar analog of the solar 5 minute oscillations can permit the determination of the radius and age of isolated stars. The key frequencies of oscillation correspond to pairs of modes differing by two in the degree of the spherical harmonic describing the angular dependence of the motion and by one in the overtone order of the modes. The frequency pairs are very nearly degenerate, and adequate frequency resolution will require a nearly unbroken time sequence extending over 15 days.},
  journal = {Astrophys. J. Lett.},
  keywords = {Cepheid Variables,Chronology,Plasma Diagnostics,Plasma Frequencies,Seismology,Stellar Evolution,Stellar Models,Stellar Oscillations}
}

@article{Ulrich1986a,
  title = {Determination of Stellar Ages from Asteroseismology},
  author = {Ulrich, R. K.},
  year = {1986},
  month = jul,
  volume = {306},
  pages = {L37-L40},
  doi = {10.1086/184700},
  abstract = {This Letter shows that measurements of the stellar analog of the solar 5 minute oscillations can permit the determination of the radius and age of isolated stars. The key frequencies of oscillation correspond to pairs of modes differing by two in the degree of the spherical harmonic describing the angular dependence of the motion and by one in the overtone order of the modes. The frequency pairs are very nearly degenerate, and adequate frequency resolution will require a nearly unbroken time sequence extending over 15 days.},
  journal = {Astrophys. J. Lett.},
  keywords = {Cepheid Variables,Chronology,Plasma Diagnostics,Plasma Frequencies,Seismology,Stellar Evolution,Stellar Models,Stellar Oscillations}
}

@article{Valle.DellOmodarme.ea2014,
  title = {Uncertainties in Grid-Based Estimates of Stellar Mass and Radius. {{SCEPtER}}: {{Stellar CharactEristics Pisa Estimation gRid}}},
  shorttitle = {Uncertainties in Grid-Based Estimates of Stellar Mass and Radius. {{SCEPtER}}},
  author = {Valle, G. and Dell'Omodarme, M. and Prada Moroni, P. G. and Degl'Innocenti, S.},
  year = {2014},
  month = jan,
  volume = {561},
  pages = {A125},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201322210},
  abstract = {Context. The availability of high-quality astero-seismological data  provided by satellite missions stimulated the development of several grid-based estimation techniques to determine the stellar masses and radii. Some aspects of the systematic and statistical errors affecting these techniques have still not been investigated well. Aims: We study the impact on mass and radius determination of the uncertainty in the input physics, in the mixing-length value, in the initial helium abundance, and in the microscopic diffusion efficiency adopted in stellar model computations. Methods: We consider stars with mass in the range [0.8-1.1] M{$\odot$} and evolutionary stages from the zero-age main sequence to the central hydrogen exhaustion. To recover the stellar parameters, a maximum-likelihood technique was employed by comparing the observations constraints to a precomputed grid of stellar models. Synthetic grids with perturbed input were adopted to estimate the systematic errors arising from the current uncertainty in model computations. Results: We found that the statistical error components, owing to the current typical uncertainty in the observations, are nearly constant in all cases at about 4.5\% and 2.2\% on mass and radius determination, respectively. The systematic bias on mass and radius determination due to a variation of {$\pm$} 1 in {$\Delta$}Y/{$\Delta$}Z is {$\pm$}2.3\% and {$\pm$} 1.1\%; the one due to a change of {$\pm$} 0.24 in the value of the mixing-length {$\alpha$}ml is {$\pm$} 2.1\% and {$\pm$} 1.0\%; the one due to a variation of {$\pm$} 5\% in the radiative opacity is {$\mp$} 1.0\% and {$\mp$} 0.45\%. An important bias source is to neglect microscopic diffusion, which accounts for errors of about 3.7\% and 1.5\% on mass and radius. The cumulative effects of the considered uncertainty sources can produce biased estimates of stellar characteristics. Comparison of the results of our technique with other grid techniques shows that the systematic biases induced by the differences in the estimation grids are generally greater than the statistical errors involved. Appendix A, Table 1, Figs. 6, 8-11, 13, 14 are available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {asteroseismology,methods: statistical,stars: evolution,stars: low-mass,stars: oscillations}
}

@article{Valle.DellOmodarme.ea2015,
  title = {Uncertainties in Asteroseismic Grid-Based Estimates of Stellar Ages. {{SCEPtER}}: {{Stellar CharactEristics Pisa Estimation gRid}}},
  shorttitle = {Uncertainties in Asteroseismic Grid-Based Estimates of Stellar Ages. {{SCEPtER}}},
  author = {Valle, G. and Dell'Omodarme, M. and Prada Moroni, P. G. and Degl'Innocenti, S.},
  year = {2015},
  month = mar,
  volume = {575},
  pages = {A12},
  issn = {0004-6361},
  doi = {10.1051/0004-6361/201424686},
  abstract = {Context. Stellar age determination by means of grid-based techniques  that adopt asteroseismic constraints is a well established method nowadays. However some theoretical aspects of the systematic and statistical errors affecting these age estimates still have to be investigated. Aims: We study the impact on stellar age determination of the uncertainty in the radiative opacity, in the initial helium abundance, in the mixing-length value, in the convective core overshooting, and in the microscopic diffusion efficiency adopted in stellar model computations. Methods: We extended our SCEPtER grid to include stars with mass in the range [0.8; 1.6] M{$\odot$} and evolutionary stages from the zero-age main sequence to the central hydrogen depletion. For the age estimation we adopted the same maximum likelihood technique as described in our previous work. To quantify the systematic errors arising from the current uncertainty in model computations, many synthetic grids of stellar models with perturbed input were adopted. Results: We found that the current typical uncertainty in the observations accounts for 1{$\sigma$} statistical relative error in age determination, which on average ranges from about -35\% to +42\%, depending on the mass. However, owing to the strong dependence on the evolutionary phase, the age's relative error can be higher than 120\% for stars near the zero-age main sequence, while it is typically of the order of 20\% or lower in the advanced main-sequence phase. The systematic bias on age determination due to a variation of {$\pm$}1 in the helium-to-metal enrichment ratio {$\Delta$}Y/{$\Delta$}Z is about one-fourth of the statistical error in the first 30\% of the evolution, while it is negligible for more evolved stages. The maximum bias due to the presence of the convective core overshooting is -7\% and -13\% for mild and strong overshooting scenarios. For all the examined models, the impact of a variation of {$\pm$}5\% in the radiative opacity was found to be negligible. The most important source of bias is the uncertainty in the mixing-length value {$\alpha$}ml and the neglect of microscopic diffusion. Each of these effects accounts for a bias that is nearly equal to the random error uncertainty. Comparison of the results of our technique with other grid techniques on a set of common stars showed general agreement. However, the adoption of a different grid can account for a variation in the mean estimated age up to 1 Gyr. Appendices are available in electronic form at http://www.aanda.org},
  journal = {A\&A},
  keywords = {asteroseismology,methods: statistical,stars: evolution,stars: fundamental parameters,stars: low-mass,stars: oscillations}
}

@article{Vandenberg1985,
  title = {Evolution of 0.7-3.0 Solar Masses Stars Having {{Fe}}/{{H}} between -1.0 and 0.0},
  author = {Vandenberg, D. A.},
  year = {1985},
  month = aug,
  volume = {58},
  pages = {711--769},
  doi = {10.1086/191055},
  abstract = {Post-main sequence tracks for 18 masses in the mass/solar mass range between 0.7 and 3.0 have been computed for each of five metal abundances. All of the calculations assumed an initial helium content of 0.25 and a value of 1.6 for the usual mixing-length parameter. The latest Los Alamos opacities, which have important ramifications for predicted mass-luminosity relations, were utilized. Isochrones for ages ranging from 300 million to 15 billion yr were calculated for each grid and transposed to the (Mv, B-V) plane using model atmospheres. The latter are also used to provide boundary conditions for stellar interior calculations. The isochrones were compared to relevant synthetic C-M diagrams of the Pleiades. Praesepe, M67, NGC 188, and NGC 2420 open clusters to check the accuracy of the calculations. The agreement was generally found to be good.},
  journal = {ApJS},
  keywords = {Abundance,Color-Magnitude Diagram,Computational Astrophysics,Hydrogen,Interstellar Extinction,Iron,Metallicity,Milky Way Galaxy,Nuclear Reactions,Open Clusters,Pleiades Cluster,Praesepe Star Clusters,Star Clusters,Stellar Evolution,Stellar Interiors,Stellar Mass,Stellar Models,Tables (Data)}
}

@article{VanderPlas2018,
  title = {Understanding the {{Lomb}}-{{Scargle Periodogram}}},
  author = {VanderPlas, Jacob T.},
  year = {2018},
  month = may,
  volume = {236},
  pages = {16},
  issn = {0067-0049},
  doi = {10.3847/1538-4365/aab766},
  abstract = {The Lomb-Scargle periodogram is a well-known algorithm for detecting and characterizing periodic signals in unevenly sampled data. This paper presents a conceptual introduction to the Lomb-Scargle periodogram and important practical considerations for its use. Rather than a rigorous mathematical treatment, the goal of this paper is to build intuition about what assumptions are implicit in the use of the Lomb-Scargle periodogram and related estimators of periodicity, so as to motivate important practical considerations required in its proper application and interpretation.},
  journal = {ApJS},
  keywords = {methods: data analysis,methods: statistical}
}

@article{Verma.Faria.ea2014,
  title = {Asteroseismic {{Estimate}} of {{Helium Abundance}} of a {{Solar Analog Binary System}}},
  author = {Verma, Kuldeep and Faria, Jo{\~a}o P. and Antia, H. M. and Basu, Sarbani and Mazumdar, Anwesh and Monteiro, M{\'a}rio J. P. F. G. and Appourchaux, Thierry and Chaplin, William J. and Garc{\'i}a, Rafael A. and Metcalfe, Travis S.},
  year = {2014},
  month = aug,
  volume = {790},
  pages = {138},
  doi = {10.1088/0004-637X/790/2/138},
  abstract = {16 Cyg A and B are among the brightest stars observed by Kepler. What makes these stars more interesting is that they are solar analogs. 16 Cyg A and B exhibit solar-like oscillations. In this work we use oscillation frequencies obtained using 2.5 yr of Kepler data to determine the current helium abundance of these stars. For this we use the fact that the helium ionization zone leaves a signature on the oscillation frequencies and that this signature can be calibrated to determine the helium abundance of that layer. By calibrating the signature of the helium ionization zone against models of known helium abundance, the helium abundance in the envelope of 16 Cyg A is found to lie in the range of 0.231 to 0.251 and that of 16 Cyg B lies in the range of 0.218 to 0.266.},
  journal = {ApJ},
  keywords = {stars: abundances,stars: individual: HD 186408 HD 186427,stars: interiors,stars: oscillations,stars: solar-type}
}

@article{Verma.Hanasoge.ea2016,
  title = {Asteroseismic Determination of Fundamental Parameters of {{Sun}}-like Stars Using Multilayered Neural Networks},
  author = {Verma, Kuldeep and Hanasoge, Shravan and Bhattacharya, Jishnu and Antia, H. M. and Krishnamurthi, Ganapathy},
  year = {2016},
  month = oct,
  volume = {461},
  pages = {4206--4214},
  issn = {0035-8711},
  doi = {10.1093/mnras/stw1621},
  abstract = {The advent of space-based observatories such as Convection, Rotation and  planetary Transits (CoRoT) and Kepler has enabled the testing of our understanding of stellar evolution on thousands of stars. Evolutionary models typically require five input parameters, the mass, initial helium abundance, initial metallicity, mixing length (assumed to be constant over time), and the age to which the star must be evolved. Some of these parameters are also very useful in characterizing the associated planets and in studying Galactic archaeology. How to obtain these parameters from observations rapidly and accurately, specifically in the context of surveys of thousands of stars, is an outstanding question, one that has eluded straightforward resolution. For a given star, we typically measure the effective temperature and surface metallicity spectroscopically and low-degree oscillation frequencies through space observatories. Here we demonstrate that statistical learning, using artificial neural networks, is successful in determining the evolutionary parameters based on spectroscopic and seismic measurements. Our trained networks show robustness over a broad range of parameter space, and critically, are entirely computationally inexpensive and fully automated. We analyse the observations of a few stars using this method and the results compare well to inferences obtained using other techniques. This method is both computationally cheap and inferentially accurate, paving the way for analysing the vast quantities of stellar observations from past, current, and future missions.},
  journal = {MNRAS},
  keywords = {stars: fundamental parameters,stars: interiors,stars: low-mass,stars: oscillations,stars: solar-type}
}

@article{Verma.Raodeo.ea2017,
  title = {Seismic {{Measurement}} of the {{Locations}} of the {{Base}} of {{Convection Zone}} and {{Helium Ionization Zone}} for {{Stars}} in the {{Kepler Seismic LEGACY Sample}}},
  author = {Verma, Kuldeep and Raodeo, Keyuri and Antia, H. M. and Mazumdar, Anwesh and Basu, Sarbani and Lund, Mikkel N. and Silva Aguirre, V{\'i}ctor},
  year = {2017},
  month = mar,
  volume = {837},
  pages = {47},
  doi = {10.3847/1538-4357/aa5da7},
  abstract = {Acoustic glitches are regions inside a star where the sound speed or its  derivatives change abruptly. These leave a small characteristic oscillatory signature in the stellar oscillation frequencies. With the precision achieved by Kepler seismic data, it is now possible to extract these small amplitude oscillatory signatures, and infer the locations of the glitches. We perform glitch analysis for all the 66 stars in the Kepler seismic LEGACY sample to derive the locations of the base of the envelope convection zone (CZ) and the helium ionization zone. The signature from helium ionization zone is found to be robust for all stars in the sample, whereas the CZ signature is found to be weak and problematic, particularly for relatively massive stars with large errorbars on the oscillation frequencies. We demonstrate that the helium glitch signature can be used to constrain the properties of the helium ionization layers and the helium abundance.},
  journal = {ApJ},
  keywords = {stars: fundamental parameters,stars: interiors,stars: oscillations,stars: solar-type}
}

@article{Verma.Raodeo.ea2019,
  title = {Helium Abundance in a Sample of Cool Stars: Measurements from Asteroseismology},
  shorttitle = {Helium Abundance in a Sample of Cool Stars},
  author = {Verma, Kuldeep and Raodeo, Keyuri and Basu, Sarbani and Silva Aguirre, V{\'i}ctor and Mazumdar, Anwesh and Mosumgaard, Jakob R{\o}rsted and Lund, Mikkel N. and Ranadive, Pritesh},
  year = {2019},
  month = mar,
  volume = {483},
  pages = {4678--4694},
  issn = {0035-8711},
  doi = {10.1093/mnras/sty3374},
  abstract = {The structural stratification of a solar-type main-sequence star primarily depends on its mass and chemical composition. The surface heavy element abundances of the solar-type stars are reasonably well determined using conventional spectroscopy; however, the second most abundant element helium is not. This is due to the fact that the envelope temperature of such stars is not high enough to excite helium. Since the helium abundance of a star affects its structure and subsequent evolution, the uncertainty in the helium abundance of a star makes estimates of its global properties (mass, radius, age etc.) uncertain as well. The detections of the signatures of the acoustic glitches from the precisely measured stellar oscillation frequencies provide an indirect way to estimate the envelope helium content. We use the glitch signature caused by the ionization of helium to determine the envelope helium abundance of 38 stars in the Kepler seismic LEGACY sample. Our results confirm that atomic diffusion does indeed take place in solar-type stars. We use the measured surface abundances in combination with the settling predicted by the stellar models to determine the initial abundances. The initial helium and metal mass fractions have subsequently been used to get the preliminary estimates of the primordial helium abundance, Yp = 0.244 {$\pm$} 0.019, and the Galactic enrichment ratio, {$\Delta$}Y/{$\Delta$}Z = 1.226 {$\pm$} 0.849. Although the current estimates have large errorbars due to the limited sample size, this method holds great promises to determine these parameters precisely in the era of upcoming space missions.},
  journal = {MNRAS},
  keywords = {stars: abundances,stars: fundamental parameters,stars: interiors,stars: oscillations,stars: solar-type}
}

@article{Viani.Basu.ea2018,
  title = {Investigating the {{Metallicity}}-{{Mixing}}-Length {{Relation}}},
  author = {Viani, Lucas S. and Basu, Sarbani and Ong J., M. Joel and Bonaca, Ana and Chaplin, William J.},
  year = {2018},
  month = may,
  volume = {858},
  pages = {28},
  doi = {10.3847/1538-4357/aab7eb},
  abstract = {Stellar models typically use the mixing-length approximation as a way to implement convection in a simplified manner. While conventionally the value of the mixing-length parameter, {$\alpha$}, used is the solar-calibrated value, many studies have shown that other values of {$\alpha$} are needed to properly model stars. This uncertainty in the value of the mixing-length parameter is a major source of error in stellar models and isochrones. Using asteroseismic data, we determine the value of the mixing-length parameter required to properly model a set of about 450 stars ranging in log g, \{T\}eff\vphantom\{\}, and [\{Fe\}/\{\{H\}\}]. The relationship between the value of {$\alpha$} required and the properties of the star is then investigated. For Eddington atmosphere, non-diffusion models, we find that the value of {$\alpha$} can be approximated by a linear model, in the form of {$\alpha$} /\{{$\alpha$} \}{$\odot$} =5.426\{--\}0.101 \{log\}(g)-1.071 \{log\}(\{T\}eff\vphantom\{\}) +0.437([\{Fe\}/\{\{H\}\}]). This process is repeated using a variety of model physics, as well as compared with previous studies and results from 3D convective simulations.},
  journal = {ApJ},
  keywords = {stars: fundamental parameters,stars: interiors,stars: oscillations: including pulsations}
}

@article{Villante.Serenelli.ea2014,
  title = {The {{Chemical Composition}} of the {{Sun}} from {{Helioseismic}} and {{Solar Neutrino Data}}},
  author = {Villante, Francesco L. and Serenelli, Aldo M. and Delahaye, Franck and Pinsonneault, Marc H.},
  year = {2014},
  month = may,
  volume = {787},
  pages = {13},
  doi = {10.1088/0004-637X/787/1/13},
  abstract = {We perform a quantitative analysis of the solar composition problem by using a statistical approach that allows us to combine the information provided by helioseismic and solar neutrino data in an effective way. We include in our analysis the helioseismic determinations of the surface helium abundance and of the depth of the convective envelope, the measurements of the 7Be and 8B neutrino fluxes, and the sound speed profile inferred from helioseismic frequencies. We provide all the ingredients to describe how these quantities depend on the solar surface composition, different from the initial and internal composition due to the effects of diffusion and nuclear reactions, and to evaluate the (correlated) uncertainties in solar model predictions. We include error sources that are not traditionally considered such as those from inversion of helioseismic data. We, then, apply the proposed approach to infer the chemical composition of the Sun. Our result is that the opacity profile of the Sun is well constrained by the solar observational properties. In the context of a two-parameter analysis in which elements are grouped as volatiles (i.e., C, N, O, and Ne) and refractories (i.e., Mg, Si, S, and Fe), the optimal surface composition is found by increasing the abundance of volatiles by (45 {$\pm$} 4)\% and that of refractories by (19 {$\pm$} 3)\% with respect to the values provided by Asplund et al. (2009, ARA\&A, 47, 481). This corresponds to the abundances {$\varepsilon$}O = 8.85 {$\pm$} 0.01 and {$\varepsilon$}Fe = 7.52 {$\pm$} 0.01, which are consistent at the \textasciitilde 1{$\sigma$} level with those provided by Grevesse \& Sauval (1998, SSRv, 85, 161). As an additional result of our analysis, we show that the best fit to the observational data is obtained with values of input parameters of the standard solar models (radiative opacities, gravitational settling rate, and the astrophysical factors S 34 and S 17) that differ at the \textasciitilde 1{$\sigma$} level from those presently adopted.},
  journal = {ApJ},
  keywords = {neutrinos,Sun: abundances,Sun: helioseismology,Sun: interior}
}

@article{vonHippel.Jefferys.ea2006,
  title = {Inverting {{Color}}-{{Magnitude Diagrams}} to {{Access Precise Star Cluster Parameters}}: {{A Bayesian Approach}}},
  shorttitle = {Inverting {{Color}}-{{Magnitude Diagrams}} to {{Access Precise Star Cluster Parameters}}},
  author = {{von Hippel}, Ted and Jefferys, William H. and Scott, James and Stein, Nathan and Winget, D. E. and DeGennaro, Steven and Dam, Albert and Jeffery, Elizabeth},
  year = {2006},
  month = jul,
  volume = {645},
  pages = {1436--1447},
  issn = {0004-637X, 1538-4357},
  doi = {10.1086/504369},
  abstract = {We demonstrate a new Bayesian technique to invert color-magnitude diagrams of main-sequence and white dwarf stars to reveal the underlying cluster properties of age, distance, metallicity, and line-of-sight absorption, as well as individual stellar masses. The advantages our technique has over traditional analyses of color-magnitude diagrams are objectivity, precision, and explicit dependence on prior knowledge of cluster parameters. Within the confines of a given set of often-used models of stellar evolution, a single mapping of initial to final masses, and white dwarf cooling, and assuming photometric errors that one could reasonably achieve with the Hubble Space Telescope, our technique yields exceptional precision for even modest numbers of cluster stars. For clusters with 50\textendash 400 members and one to a few dozen white dwarfs, we find typical internal errors of  ({$\frac{1}{2}$}Fe/ H Š) 0:03 dex,  (m \`A MV ) 0:02 mag, and  (AV ) 0:01 mag. We derive cluster white dwarf ages with internal errors of typically only 10\% for clusters with only three white dwarfs and almost always 5\% with 10 white dwarfs. These exceptional precisions will allow us to test white dwarf cooling models and standard stellar evolution models through observations of white dwarfs in open and globular clusters.},
  journal = {ApJ},
  keywords = {bayesian inference,cluster ages,clusters,colour-magnitude diagrams},
  language = {en},
  number = {2}
}

@article{Vrard.Mosser.ea2015,
  title = {Helium Signature in Red Giant Oscillation Patterns Observed by {{{\emph{Kepler}}}}},
  author = {Vrard, M. and Mosser, B. and Barban, C. and Belkacem, K. and Elsworth, Y. and Kallinger, T. and Hekker, S. and Samadi, R. and Beck, P. G.},
  year = {2015},
  month = jul,
  volume = {579},
  pages = {A84},
  issn = {0004-6361, 1432-0746},
  doi = {10.1051/0004-6361/201425064},
  abstract = {Context. The space-borne missions CoRoT and Kepler have provided a large amount of precise photometric data. Among the stars observed, red giants show a rich oscillation pattern that allows their precise characterization. Long-duration observations allow for investigating the fine structure of this oscillation pattern Aims. A common pattern of oscillation frequency was observed in red giant stars, which corresponds to the second-order development of the asymptotic theory. This pattern, called the universal red giant oscillation pattern, describes the frequencies of stellar acoustic modes. We aim to investigate the deviations observed from this universal pattern, thereby characterizing them in terms of the location of the second ionization zone of helium. We also show how this seismic signature depends on stellar evolution.},
  journal = {A\&A},
  keywords = {asteroseismology,helium},
  language = {en}
}

@article{Weiss.Schlattl2008,
  title = {{{GARSTEC}}\textemdash the {{Garching Stellar Evolution Code}}. {{The}} Direct Descendant of the Legendary {{Kippenhahn}} Code},
  author = {Weiss, Achim and Schlattl, Helmut},
  year = {2008},
  month = aug,
  volume = {316},
  pages = {99--106},
  doi = {10.1007/s10509-007-9606-5},
  abstract = {We describe the Garching Stellar Evolution Code. General features,  treatment of the microphysics, details of the numerical solution, handling and particularities are discussed. The standard solar model serves as the most basic benchmark to test the accurateness of the code and is presented, too.},
  journal = {Ap\&SS}
}

@article{West.Heger2013,
  title = {Metallicity-Dependent {{Galactic Isotopic Decomposition}} for {{Nucleosynthesis}}},
  author = {West, Christopher and Heger, Alexander},
  year = {2013},
  month = sep,
  volume = {774},
  pages = {75},
  doi = {10.1088/0004-637X/774/1/75},
  abstract = {All stellar evolution models for nucleosynthesis require an initial isotopic abundance set to use as a starting point. Generally, our knowledge of isotopic abundances of stars is fairly incomplete except for the Sun. We present a first model for a complete average isotopic decomposition as a function of metallicity. Our model is based on the underlying nuclear astrophysics processes, and is fitted to observational data, rather than traditional forward galactic chemical evolution modeling which integrates stellar yields beginning from big bang nucleosynthesis. We first decompose the isotopic solar abundance pattern into contributions from astrophysical sources. Each contribution is then assumed to scale as a function of metallicity. The resulting total isotopic abundances are summed into elemental abundances and fitted to available halo and disk stellar data to constrain the model's free parameter values. This procedure allows us to use available elemental observational data to reconstruct and constrain both the much needed complete isotopic evolution that is not accessible to current observations, and the underlying astrophysical processes. As an example, our model finds a best fit for Type Ia contributing \textasciitilde = 0.7 to the solar Fe abundance, and Type Ia onset occurring at [Fe/H] \textasciitilde = -1.1, in agreement with typical values.},
  journal = {ApJ},
  keywords = {abundances,Galaxy: abundances,Galaxy: evolution,nuclear reactions,nucleosynthesis,stars: abundances,supernovae: general}
}

@article{White.Bedding.ea2011,
  title = {Calculating {{Asteroseismic Diagrams}} for {{Solar}}-like {{Oscillations}}},
  author = {White, Timothy R. and Bedding, Timothy R. and Stello, Dennis and {Christensen-Dalsgaard}, J{\o}rgen and Huber, Daniel and Kjeldsen, Hans},
  year = {2011},
  month = dec,
  volume = {743},
  pages = {161},
  issn = {0004-637X},
  doi = {10.1088/0004-637X/743/2/161},
  abstract = {With the success of the Kepler and CoRoT missions, the number of stars with detected solar-like oscillations has increased by several orders of magnitude; for the first time we are able to perform large-scale ensemble asteroseismology of these stars. In preparation for this golden age of asteroseismology we have computed expected values of various asteroseismic observables from models of varying mass and metallicity. The relationships between these asteroseismic observables, such as the separations between mode frequencies, are able to significantly constrain estimates of the ages and masses of these stars. We investigate the scaling relation between the large frequency separation, {$\Delta\nu$}, and mean stellar density. Furthermore we present model evolutionary tracks for several asteroseismic diagrams. We have extended the so-called C-D diagram beyond the main sequence to the subgiants and the red giant branch. We also consider another asteroseismic diagram, the epsilon diagram, which is more sensitive to variations in stellar properties at the subgiant stages and can aid in determining the correct mode identification. The recent discovery of gravity-mode period spacings in red giants forms the basis for a third asteroseismic diagram. We compare the evolutionary model tracks in these asteroseismic diagrams with results from pre-Kepler studies of solar-like oscillations and early results from Kepler.},
  journal = {ApJ},
  keywords = {stars: fundamental parameters,stars: interiors,stars: oscillations}
}

@article{Yakovlev.Urpin1980,
  title = {Thermal and {{Electrical Conductivity}} in {{White Dwarfs}} and {{Neutron Stars}}},
  author = {Yakovlev, D. G. and Urpin, V. A.},
  year = {1980},
  month = jun,
  volume = {24},
  pages = {303},
  issn = {0038-5301},
  abstract = {Not Available},
  journal = {SvA}
}

@article{Zinn.Pinsonneault.ea2019,
  title = {Confirmation of the {{Gaia DR2 Parallax Zero}}-Point {{Offset Using Asteroseismology}} and {{Spectroscopy}} in the {{Kepler Field}}},
  author = {Zinn, Joel C. and Pinsonneault, Marc H. and Huber, Daniel and Stello, Dennis},
  year = {2019},
  month = jun,
  volume = {878},
  pages = {136},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/ab1f66},
  abstract = {We present an independent confirmation of the zero-point offset of Gaia  Data Release 2 parallaxes using asteroseismic data of evolved stars in the Kepler field. Using well-characterized red giant branch stars from the APOKASC-2 catalog, we identify a Gaia astrometric pseudocolor (\{{$\nu$} \}eff\vphantom\{\})- and Gaia G-band magnitude-dependent zero-point offset of \{\textbackslash varpi \}seis\vphantom\{\} - \{\textbackslash varpi \}\{Gaia\} = 52.8 {$\pm$} 2.4 (rand.) {$\pm$} 8.6 (syst.) - (150.7 {$\pm$} 22.7)(\{{$\nu$} \}eff\vphantom\{\} - 1.5) - (4.21 {$\pm$} 0.77)(G - 12.2) {$\mu$}as, in the sense that Gaia parallaxes are too small. The offset is found in high- and low-extinction samples, as well as among both shell H-burning red giant stars and core He-burning red clump stars. We show that errors in the asteroseismic radius and temperature scales may be distinguished from errors in the Gaia parallax scale. We estimate systematic effects on the inferred global Gaia parallax offset, c, due to radius and temperature systematics, as well as choices in bolometric correction and the adopted form for Gaia parallax spatial correlations. Because of possible spatially correlated parallax errors, as discussed by the Gaia team, our Gaia parallax offset model is specific to the Kepler field, but broadly compatible with the magnitude- and color-dependent offset inferred by the Gaia team and several subsequent investigations using independent methods.},
  journal = {ApJ},
  keywords = {asteroseismology,catalogs,parallaxes,stars: distances}
}

@article{Zinn.Pinsonneault.ea2019a,
  title = {Testing the {{Radius Scaling Relation}} with {{Gaia DR2}} in the {{Kepler Field}}},
  author = {Zinn, Joel C. and Pinsonneault, Marc H. and Huber, Daniel and Stello, Dennis and Stassun, Keivan and Serenelli, Aldo},
  year = {2019},
  month = nov,
  volume = {885},
  pages = {166},
  issn = {0004-637X},
  doi = {10.3847/1538-4357/ab44a9},
  abstract = {We compare radii based on Gaia parallaxes to radii based on asteroseismic scaling relations for {$\sim$}300 dwarfs and subgiants and {$\sim$}3600 first-ascent giants from the Kepler mission. Systematics due to temperature, bolometric correction, extinction, asteroseismic radius, and the spatially correlated Gaia parallax zero-point contribute to a 2\% systematic uncertainty on the agreement in Gaia\textendash asteroseismic radius. We find that dwarf and giant scaling radii are on a parallactic scale at the level of -2.1\% {$\pm$} 0.5\% (rand.) {$\pm$} 2.0\% (syst.) (dwarfs) and +1.7\% {$\pm$} 0.3\% (rand.) {$\pm$} 2.0\% (syst.) (giants), supporting the accuracy and precision of scaling relations. In total, the 2\% agreement that we find holds for stars spanning radii between 0.8 \{R\}{\.o} and 30 \{R\}{\.o} . We do, however, see evidence for relative errors in scaling radii between dwarfs and giants at the level of 4\% {$\pm$} 0.6\%, and find evidence of departures from simple scaling relations for radii above 30 \{R\}{\.o} . Asteroseismic masses for very metal-poor stars are still overestimated relative to astrophysical priors, but at a reduced level. We see no trend with metallicity in radius agreement for stars with -0.5 {$<$} [Fe/H] {$<$} +0.5. We quantify the spatially correlated parallax errors in the Kepler field, which globally agree with the Gaia team's published covariance model. We provide Gaia radii, corrected for extinction and the Gaia parallax zero-point, for our full sample of {$\sim$}3900 stars, including dwarfs, subgiants, and first-ascent giants.},
  journal = {ApJ},
  keywords = {asteroseismology,catalogs,parallaxes,stars: fundamental parameters,stars: low-mass}
}