• DOI:10.1088/0004-637X/810/1/30
• Corpus ID: 17747458

KELT-8b: A Highly Inflated Transiting Hot Jupiter and a New Technique for Extracting High-precision Radial Velocities from Noisy Spectra

@article{Fulton2015KELT8bAH,
  title={KELT-8b: A Highly Inflated Transiting Hot Jupiter and a New Technique for Extracting High-precision Radial Velocities from Noisy Spectra},
  author={Benjamin J. Fulton and Karen A. Collins and B. Scott Gaudi and Keivan G. Stassun and Joshua A. Pepper and Thomas G. Beatty and Robert J. Siverd and Kaloyan Penev and Andrew W. Howard and Christoph Baranec and Giorgio Corfini and Jason D. Eastman and Joao Gregorio and Nicholas M. Law and Michael B. Lund and Thomas E. Oberst and Matthew T. Penny and Reed L. Riddle and Joseph E. Rodriguez and Daniel J. Stevens and Roberto Zambelli and Carl A. Ziegler and Allyson Bieryla and G. D{\'A}go and Darren Lee Depoy and Eric L. N. Jensen and John F. Kielkopf and David W. Latham and Mark Manner and Jennifer L. Marshall and Kim K. McLeod and Phillip A. Reed},
  journal={The Astrophysical Journal},
  year={2015},
  volume={810},
  pages={30}
}

• B. Fulton, K. Collins, +29 authors P. Reed
• Published 25 May 2015
• Geology, Physics
• The Astrophysical Journal

We announce the discovery of a highly inflated transiting hot Jupiter by the KELT-North survey. A global analysis including constraints from isochrones indicates that the V = 10.8 host star (HD 343246) is a mildly evolved, G dwarf
with T_(eff)= 5754^(+54)_(-55)K, log g = 4.078^(0.049)_(0.054), [Fe/H] = 0.272 ± 0.038, an inferred mass M_* = 1.211_(0.066)^(+0.078)M_☉, and radius R_*=1.67 _(-0.12)^(+0.14) R_☉. The planetary companion has a mass Mp = 0.867 _(-0.061)^+(0.065) MJ, radius R_p 1.86_(-0.16)^(+0.18) R_J, surface gravity log g_p 2.793_(-0.075)^(+0.072), and density 0.167_(-0.038)^(+0.047) g cm^(−3). The planet is on a roughly circular orbit with semimajor axis ɑ 0.04571_(0.00084)^(+0.00096) AU and eccentricity e 0.035_(-0.025)^(+0.050). The best-fit linear ephemeris is T_0 = 2456883.4803 ± 0.0007 BJD_(TDB) and P = 3.24406 ± 0.00016 days. This planet is one of the most inflated of all known transiting exoplanets, making it one of the few members of a class of extremely low density, highly irradiated gas giants. The low stellar log g and large implied radius are supported by stellar density constraints from follow-up light curves, as well as an evolutionary and space motion analysis. We also develop a new technique to extract high-precision radial velocities from noisy spectra that reduces the observing time needed to confirm transiting planet candidates. This planet boasts deep transits of a bright star, a large inferred atmospheric scale height, and a high equilibrium temperature of T_(eq) 1675_(-55)^(+61)K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.