@article{0fa37002b8d84916bdd1df1743525818,
title = "Kepler-503b: An Object at the Hydrogen Burning Mass Limit Orbiting a Subgiant Star",
abstract = "Using spectroscopic radial velocities with the Apache Point Observatory Galaxy Evolution Experiment (APOGEE) instrument and Gaia distance estimates, we demonstrate that Kepler-503b, currently considered a validated Kepler planet, is in fact a brown-dwarf/low-mass star in a nearly circular 7.2-day orbit around a subgiant star. Using a mass estimate for the primary star derived from stellar models, we derive a companion mass and radius of 0.075 ±0.003 M o (78.6 ± 3.1 M Jup) and ( R Jup), respectively. Assuming that the system is coeval, the evolutionary state of the primary indicates the age is ∼6.7 Gyr. Kepler-503b sits right at the hydrogen-burning mass limit, straddling the boundary between brown dwarfs and very low-mass stars. More precise radial velocities and secondary eclipse spectroscopy with the James Webb Space Telescope (JWST) will provide improved measurements of the physical parameters and age of this important system to better constrain and understand the physics of these objects and their spectra. This system emphasizes the value of radial velocity observations to distinguish a genuine planet from astrophysical false positives, and is the first result from the Sloan Digital Sky Survey (SDSS)-IV monitoring of Kepler planet candidates with the multi-object APOGEE instrument.",
keywords = "binaries: eclipsing, stars: low-mass, techniques: photometric, techniques: spectroscopic",
author = "Canas, {Caleb I.} and Bender, {Chad F.} and Suvrath Mahadevan and Fleming, {Scott W.} and Beatty, {Thomas G.} and Covey, {Kevin R.} and Lee, {Nathan De} and Hearty, {Fred R.} and Garcia-Hern{\'a}ndez, {D. A.} and Majewski, {Steven R.} and Schneider, {Donald P.} and Stassun, {Keivan G.} and Wilson, {Robert F.}",
note = "Funding Information: We thank the anonymous referee for comments that improved the quality of this publication. C.I.C., C.F.B., and S.M. acknowledge support from NSF award AST 1517592. N.D., S.R.M., and R.F.W. would like to acknowledge support from NSF grant Nos. 1616684 and 1616636. D.A.G.H. acknowledges support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) under grant AYA-2017-88254-P. Some of the data presented in this Letter were obtained from MAST. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. 2MASS is a joint project of the University of Massachusetts and IPAC at Caltech, funded by NASA and the NSF. Funding for the Kepler mission is provided by the NASA Science Mission directorate. The NASA Exoplanet Archive is operated by Caltech, under contract with NASA under the Exoplanet Exploration Program. Funding Information: Funding for SDSS-IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is http://www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrof{\'i}sica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut f{\"u}r Astrophysik Potsdam (AIP), Max-Planck-Institut f{\"u}r Astronomie (MPIA Heidelberg), Max-Planck-Institut f{\"u}r Astrophysik (MPA Garching), Max-Planck-Institut f{\"u}r Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observat{\'a}rio Nacional/MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Uni-versidad Nacional Aut{\'o}noma de M{\'e}xico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University. Publisher Copyright: {\textcopyright} 2018. The American Astronomical Society. All rights reserved..",
year = "2018",
month = jul,
day = "1",
doi = "10.3847/2041-8213/aacbc5",
language = "English (US)",
volume = "861",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1",
}