KELT-8b: A HIGHLY INFLATED TRANSITING HOT JUPITER AND A NEW TECHNIQUE FOR EXTRACTING HIGH-PRECISION RADIAL VELOCITIES FROM NOISY SPECTRA Academic Article uri icon

abstract

  • 2015. The American Astronomical Society. All rights reserved. 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 Teff = 5754-55+54 K, log g = 4.078-0.054+0.049, [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 RP = 1.86-0.16+0.18 RJ, surface gravity log gP = 2.793-0.075+0.072, and density P = 0.167-0.038+0.047 g cm-3. The planet is on a roughly circular orbit with semimajor axis a = 0.04571-0.00084+0.00096 AU and eccentricity e = 0.035-0.025+0.050. The best-fit linear ephemeris is T0 = 2456883.4803 0.0007 BJDTDB 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 Teq = 1675-55+61 K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.

published proceedings

  • ASTROPHYSICAL JOURNAL

altmetric score

  • 7.6

author list (cited authors)

  • Fulton, B. J., Collins, K. A., Gaudi, B. S., Stassun, K. G., Pepper, J., Beatty, T. G., ... Reed, P. A.

citation count

  • 37

complete list of authors

  • Fulton, Benjamin J||Collins, Karen A||Gaudi, B Scott||Stassun, Keivan G||Pepper, Joshua||Beatty, Thomas G||Siverd, Robert J||Penev, Kaloyan||Howard, Andrew W||Baranec, Christoph||Corfini, Giorgio||Eastman, Jason D||Gregorio, Joao||Law, Nicholas M||Lund, Michael B||Oberst, Thomas E||Penny, Matthew T||Riddle, Reed||Rodriguez, Joseph E||Stevens, Daniel J||Zambelli, Roberto||Ziegler, Carl||Bieryla, Allyson||D'Ago, Giuseppe||DePoy, Darren L||Jensen, Eric LN||Kielkopf, John F||Latham, David W||Manner, Mark||Marshall, Jennifer||McLeod, Kim K||Reed, Phillip A

publication date

  • September 2015