TY - JOUR
T1 - KELT-2Ab
T2 - A Hot Jupiter Transiting the Bright (V = 8.77) Primary Star of a Binary System
AU - Beatty, T.G.
AU - Pepper, J.
AU - Siverd, R.J.
AU - Eastman, J.D.
AU - Bieryla, A.
AU - Latham, D.W.
AU - Buchhave, Lars C. Astrup
AU - Jensen, E.N.
AU - Manner, M.
AU - Stassun, K.G.
AU - Gaudi, B.S.
PY - 2012/9/10
Y1 - 2012/9/10
N2 - 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.
AB - 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.
U2 - 10.1088/2041-8205/756/2/L39
DO - 10.1088/2041-8205/756/2/L39
M3 - Journal article
SN - 2041-8205
VL - 756
SP - L39
JO - The Astrophysical Journal Letters
JF - The Astrophysical Journal Letters
IS - 2
ER -