HATS-9b and HATS-10b: Two Anomalously Compact hot Jupiters to be Observed by Kepler's K2 Mission

HATS-9b AND HATS-10b: TWO COMPACT HOT JUPITERS IN FIELD 7 OF THE K2 MISSION

Authors:

Brahm et al

Abstract:

We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8 ± 1.5 Gyr) V=13.3 G dwarf star, with a period P = 1.9153 d. The host star has a mass of 1.03 M⊙, radius of 1.503 R⊙ and effective temperature 5366 ± 70 K. The planetary companion has a mass of 0.837 MJ, and radius of 1.065 RJ yielding a mean density of 0.85 g cm−3 . HATS-10b orbits a V=13.1 G dwarf star, with a period P = 3.3128 d. The host star has a mass of 1.1 M⊙, radius of 1.11 R⊙ and effective temperature 5880 ± 120 K. The planetary companion has a mass of 0.53 MJ, and radius of 0.97 RJ yielding a mean density of 0.7 g cm−3 . Both planets are compact in comparison with planets receiving similar irradiation from their host stars, and lie in the nominal coordinates of Field 7 of K2 but only HATS-9b falls on working silicon. Future characterisation of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.