KELT-1b: A STRONGLY IRRADIATED, HIGHLY INFLATED, SHORT PERIOD, 27 JUPITER-MASS COMPANION TRANSITING A MID-F STAR Academic Article uri icon

abstract

  • We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) transit survey. A joint analysis of the spectroscopic, radial velocity, and photometric data indicates that the V = 10.7 primary is a mildly evolved mid-F star with T eff= 6516 49 K, log g = 4.228 +0.014-0.021, and [Fe/H] = 0.052 0.079, with an inferred mass M* = 1.335 0.063 M and radius R* = 1.471+0.045-0.035 R. The companion is a low-mass brown dwarf or a super-massive planet with mass MP= 27.38 0.93 MJup and radius RP= 1.116+0.038-0.029RJup. The companion is on a very short (29 hr) period circular orbit, with an ephemeris Tc(BJDTDB) = 2455909.29280 0.00023 and P = 1.217501 0.000018 days. KELT-1b receives a large amount of stellar insolation, resulting in an estimated equilibrium temperature assuming zero albedo and perfect redistribution of T eq= 2423+34-27 K. Comparison with standard evolutionary models suggests that the radius of KELT-1b is likely to be significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1 with a separation of 588 1 mas, which is consistent with an M dwarf if it is at the same distance as the primary. Rossiter-McLaughlin measurements during transit imply a projected spin-orbit alignment angle = 2 16 deg, consistent with a zero obliquity for KELT-1. Finally, the vsin I* = 56 2 km s-1 of the primary is consistent at 2 with tidal synchronization. Given the extreme parameters of the KELT-1 system, we expect it to provide an important testbed for theories of the emplacement and evolution of short-period companions, as well as theories of tidal dissipation and irradiated brown dwarf atmospheres. 2012. The American Astronomical Society. All rights reserved..

published proceedings

  • ASTROPHYSICAL JOURNAL

altmetric score

  • 40.45

author list (cited authors)

  • Siverd, R. J., Beatty, T. G., Pepper, J., Eastman, J. D., Collins, K., Bieryla, A., ... van Saders, J. L.

citation count

  • 220

complete list of authors

  • Siverd, Robert J||Beatty, Thomas G||Pepper, Joshua||Eastman, Jason D||Collins, Karen||Bieryla, Allyson||Latham, David W||Buchhave, Lars A||Jensen, Eric LN||Crepp, Justin R||Street, Rachel||Stassun, Keivan G||Gaudi, B Scott||Berlind, Perry||Calkins, Michael L||DePoy, DL||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||Szentgyorgyi, Andrew H||Trueblood, Mark||Trueblood, Patricia||Stutz, Amelia M||van Saders, Jennifer L

publication date

  • December 2012