KELT-8b: A highly inflated transiting hot jupiter and a new technique for extracting high-precision radial velocities from noisy spectra
- Institute for Astronomy, University of Hawai‘i, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
- Department of Physics and Astronomy, University of Louisville, Louisville, KY 40292 (United States)
- Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States)
- Department of Astronomy and Astrophysics and Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States)
- Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States)
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
- Societ Astronomica Lunae, Castelnuovo Magra I-19030, Via Montefrancio, 77—Italy (Italy)
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
- Atalaia Group and Crow-Observatory, Portalegre (Portugal)
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States)
- Department of Physics, Lehigh University, Bethlehem, PA 18015 (United States)
- Department of Physics, Westminster College, New Wilmington, PA 16172 (United States)
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
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{sub eff}=5754{sub −55}{sup +54} K, log g=4.078{sub −0.054}{sup +0.049}, [Fe/H]=0.272±0.038, an inferred mass M{sub ∗}=1.211{sub −0.066}{sup +0.078} M{sub ⊙}, and radius R{sub ∗}=1.67{sub −0.12}{sup +0.14} R{sub ⊙}. The planetary companion has a mass M{sub P}=0.867{sub −0.061}{sup +0.065} M{sub J}, radius R{sub P}=1.86{sub −0.16}{sup +0.18} R{sub J}, surface gravity log g{sub P}=2.793{sub −0.075}{sup +0.072}, and density ρ{sub P}=0.167{sub −0.038}{sup +0.047} g cm{sup −3}. The planet is on a roughly circular orbit with semimajor axis a=0.04571{sub −0.00084}{sup +0.00096} AU and eccentricity e=0.035{sub −0.025}{sup +0.050}. The best-fit linear ephemeris is T{sub 0}=2456883.4803±0.0007 BJD{sub 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{sub eq}=1675{sub −55}{sup +61} K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.
- OSTI ID:
- 22882723
- Journal Information:
- Astrophysical Journal, Vol. 810, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
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