KELT-2Ab: A HOT JUPITER TRANSITING THE BRIGHT (V=8.77) PRIMARY STAR OF A BINARY SYSTEM Academic Article uri icon

abstract

  • We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V = 8.77) primary star of the HD42176 binary system. The host is a slightly evolved late F-star likely in the very short-lived "blue-hook" stage of evolution, with T eff = 6148 48 K, log g = 4.030 +0.015- 0.026 and [Fe/H] = 0.034 0.78. The inferred stellar mass is M * = 1.314+0.063- 0.060 M and the star has a relatively large radius of R * = 1.836+0.066- 0.046 R . The planet is a typical hot Jupiter with period 4.1137913 0.00001 days and a mass of MP = 1.524 0.088 M J and radius of RP = 1.290+0.064- 0.050 R J. This is mildly inflated as compared to models of irradiated giant planets at the 4Gyr age of the system. KELT-2A is the third brightest star with a transiting planet identified by ground-based transit surveys, and the ninth brightest star overall with a transiting planet. KELT-2Ab's mass and radius are unique among the subset of planets with V < 9 host stars, and therefore increases the diversity of bright benchmark systems. We also measure the relative motion of KELT-2A and -2B over a baseline of 38years, robustly demonstrating for the first time that the stars are bound. This allows us to infer that KELT-2B is an early K dwarf. We hypothesize that through the eccentric Kozai mechanism KELT-2B may have emplaced KELT-2Ab in its current orbit. This scenario is potentially testable with Rossiter-McLaughlin measurements, which should have an amplitude of 44m s-1. 2012 The American Astronomical Society. All rights reserved.

published proceedings

  • ASTROPHYSICAL JOURNAL LETTERS

altmetric score

  • 45.05

author list (cited authors)

  • Beatty, T. G., Pepper, J., Siverd, R. J., Eastman, J. D., Bieryla, A., Latham, D. W., ... Stutz, A. M.

citation count

  • 42

complete list of authors

  • Beatty, Thomas G||Pepper, Joshua||Siverd, Robert J||Eastman, Jason D||Bieryla, Allyson||Latham, David W||Buchhave, Lars A||Jensen, Eric LN||Manner, Mark||Stassun, Keivan G||Gaudi, B Scott||Berlind, Perry||Calkins, Michael L||Collins, Karen||DePoy, Darren L||Esquerdo, Gilbert A||Fulton, Benjamin J||Furesz, Gabor||Geary, John C||Gould, Andrew||Hebb, Leslie||Kielkopf, John F||Marshall, Jennifer L||Pogge, Richard||Stanek, KZ||Stefanik, Robert P||Street, Rachel||Szentgyorgyi, Andrew H||Trueblood, Mark||Trueblood, Patricia||Stutz, Amelia M

publication date

  • September 2012