K2-237 b and K2-238 b: Discovery and characterization of two new transiting hot Jupiters from K2

Abstract

We report the discovery of two hot Jupiters orbiting the stars K2-237 and K2-238. We used photometric data from Campaigns 11 and 12 of the Kepler K2 mission and radial velocity data obtained using the HARPS, FEROS, and CORALIE spectrographs. K2-237 b and K2-238 b have masses of 1.60-0.11 +0.11 and 0.86+-0.12 0.13MJup, radii of 1.65-0.08 +0.07 and 1.30-0.14 +0.15 RJup, and are orbiting their host stars in 2.18-and 3.20-d orbits, respectively. The large radius of K2-237 b leads us to conclude that this candidate corresponds to a highly inflated hot Jupiter. K2-238 b has a radius consistent with theoretical models, considering the high incident flux falling on the planet. We consider K2-237 b to be an excellent system for follow-up studies, since not only is it very inflated, but it also orbits a relatively bright star (V = 11.6).