Kelt-10b: an Inflated hot Saturn Expected to be Destroyed Within a Billion Years

KELT-10b: The First Transiting Exoplanet from the KELT-South Survey -- A Hot Sub-Jupiter Transiting a V = 10.7 Early G-Star

Authors:

Kuhn et al

Abstract:

We report the discovery of KELT-10b, the first transiting exoplanet discovered using the KELT-South telescope. KELT-10b is a highly inflated sub-Jupiter mass planet transiting a relatively bright V=10.7 star (TYC 8378-64-1), with Teff = 5948±74 K, logg = 4.319+0.020−0.030 and [Fe/H] = 0.09+0.11−0.10, an inferred mass M∗ = 1.112+0.055−0.061 M⊙ and radius R∗ = 1.209+0.047−0.035 R⊙. The planet has a radius RP = 1.399+0.069−0.049 RJ and mass MP = 0.679+0.039−0.038 MJ. The planet has an eccentricity consistent with zero and a semi-major axis a = 0.05250+0.00086−0.00097 AU. The best fitting linear ephemeris is T0 = 2457066.72045±0.00027 BJDTDB and P = 4.1662739±0.0000063 days. This planet joins a group of highly inflated transiting exoplanets with a radius much larger and a mass much less than those of Jupiter. The planet, which boasts deep transits of 1.4%, has a relatively high equilibrium temperature of Teq = 1377+28−23 K, assuming zero albedo and perfect heat redistribution. KELT-10b receives an estimated insolation of 0.817+0.068−0.054 × 109 erg s−1 cm−2, which places it far above the insolation threshold above which hot Jupiters exhibit increasing amounts of radius inflation. Evolutionary analysis of the host star suggests that KELT-10b is unlikely to survive beyond the current subgiant phase, due to a concomitant in-spiral of the planet over the next ∼1 Gyr. The planet transits a relatively bright star which is accessible to large telescopes and exhibits the third largest transit depth of all transiting exoplanets with V less than 11 in the southern hemisphere, making it a promising candidate for future atmospheric characterization studies.