HATS9-b AND HATS10-b: TWO COMPACT HOT JUPITERS IN FIELD 7 OF THE K2 MISSION

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 days. The host star has a mass of 1.03 , radius of 1.503 , and effective temperature 5366 ± 70 K. The planetary companion has a mass of 0.837 and radius of 1.065 , yielding a mean density of 0.85 . HATS-10b orbits a V = 13.1 G dwarf star with a period days. The host star has a mass of 1.1 , radius of 1.11 , and effective temperature 5880 ± 120 K. The planetary companion has a mass of 0.53 and radius of 0.97 , yielding a mean density of 0.7 . 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 characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.