Photometry and spectroscopy of HATS-6

HATS-6b has a period of P=3.3253d, mass of M_p_=0.32M_J_, radius of R_p_=1.00R_J_, and zero-albedo equilibrium temperature of T_eq_=712.8+/-5.1K. HATS-6 is one of the lowest mass stars known to host a close-in gas giant planet, and its transits are among the deepest of any known transiting planet system.

We discuss the follow-up opportunities afforded by this system, noting that despite the faintness of the host star, it is expected to have the highest K-band S/N transmission spectrum among known gas giant planets with T_eq_<750K. In order to characterize the star we present a new set of empirical relations between the density, radius, mass, bolometric magnitude, and V-, J-, H- and K-band bolometric corrections for main sequence stars with M<0.80M_{Sun}_, or spectral types later than K5.