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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 661091.0, MPI für Astronomie / Publikationen_mpia
KELT-2Ab: a hot Jupiter transiting the bright (V = 8.77) primary star of a binary system
Authors:Beatty, T. G.; Pepper, J.; Siverd, R. J.; Eastman, J. D.; Bieryla, A.; Latham, D. W.; Buchhave, L. A.; Jensen, E. L. N.; Manner, M.; Stassun, K. G.; Gaudi, B. S.; Berlind, P.; Calkins, M. L.; Collins, K.; DePoy, D. L.; Esquerdo, G. A.; Fulton, B. J.; Fűrész, G.; Geary, J. C.; Gould, A.; Hebb, L.; Kielkopf, J. F.; Marshall, J. L.; Pogge, R.; Stanek, K. Z.; Stefanik, R. P.; Street, R.; Szentgyorgyi, A. H.; Trueblood, M.; Trueblood, P.; Stutz, A. M.
Date of Publication (YYYY-MM-DD):2012
Journal Abbrev.:The Astrophysical Journal Letters
Issue / Number:2
Start Page:id. L39
Audience:Not Specified
Abstract / Description:We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V = 8.77) primary star of the HD 42176 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 &sun; and the star has a relatively large radius of R * = 1.836+0.066 - 0.046 R &sun;. 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 ~4 Gyr 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 38 years, 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 ~44 m s-1.
Free Keywords:binaries: visual; eclipses; planetary systems; stars: individual: HD 42176; techniques: photometric; techniques: radial velocities
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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