KELT-6b: A P 7.9 DAY HOT SATURN TRANSITING A METAL-POOR STAR WITH A LONG-PERIOD COMPANION Academic Article uri icon

abstract

  • We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T eff = 6102 43 K, log g* = 4.07 +0.04-0.07, and [Fe/H] = -0.28 0.04, with an inferred mass M = 1.09 0.04M and radius R = 1.58+0.16-0.09 R . The planetary companion has mass MP = 0.43 0.05MJup, radius RP = 1.19+0.13-0.08 RJup, surface gravity log gP = 2.86+0.06-0.08, and density .P = 0.31+0.07-0.08 g cm-3. The planet is on an orbit with semimajor axis a = 0.079 0.001 AU and eccentricity e = 0.22+0.12-0.10, which is roughly consistent with circular, and has ephemeris of Tc(BJDTDB) = 2456347.79679 0.00036 and P = 7.845631 0.000046 days. Equally plausible fits that employ empirical constraints on the host-star parameters rather than isochrones yield a larger planet mass and radius by 4}-7}. KELT-6b has surface gravity and incident flux similar to HD 209458b, but orbits a host that is more metal poor than HD 209458 by 0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images. 2014. The American Astronomical Society. All rights reserved.

published proceedings

  • ASTRONOMICAL JOURNAL

altmetric score

  • 10.05

author list (cited authors)

  • Collins, K. A., Eastman, J. D., Beatty, T. G., Siverd, R. J., Gaudi, B. S., Pepper, J., ... Trueblood, P.

citation count

  • 37

complete list of authors

  • Collins, Karen A||Eastman, Jason D||Beatty, Thomas G||Siverd, Robert J||Gaudi, B Scott||Pepper, Joshua||Kielkopf, John F||Johnson, John Asher||Howard, Andrew W||Fischer, Debra A||Manner, Mark||Bieryla, Allyson||Latham, David W||Fulton, Benjamin J||Gregorio, Joao||Buchhave, Lars A||Jensen, Eric LN||Stassun, Keivan G||Penev, Kaloyan||Crepp, Justin R||Hinkley, Sasha||Street, Rachel A||Cargile, Phillip||Mack, Claude E||Oberst, Thomas E||Avril, Ryan L||Mellon, Samuel N||McLeod, Kim K||Penny, Matthew T||Stefanik, Robert P||Berlind, Perry||Calkins, Michael L||Mao, Qingqing||Richert, Alexander JW||Depoy, Darren L||Esquerdo, Gilbert A||Gould, Andrew||Marshall, Jennifer L||Oelkers, Ryan J||Pogge, Richard W||Trueblood, Mark||Trueblood, Patricia

publication date

  • February 2014