K2-232 b: a transiting warm Saturn on an eccentric P = 11.2 d orbit around a V = 9.9 star

Abstract

We report the discovery of K2-232 b using photometric data of the Kepler K2 satellite coupled with ground-based spectroscopic observations. K2-232 b has a mass of M-P = 0.397 +/- 0.037 M-J, a radius of R-P = 1.00 +/- 0.020 R-J, and a moderately low equilibrium temperature of T-eq = 1030 +/- 15K due to its relatively large star-planet separation of a = 0.1036 au. K2-232 b orbits its bright (V = 9.9) late F-type host star in an eccentric orbit (e = 0.258 +/- 0.025) every 11.2 d, and is one of only four well-characterized warm Jupiters having host stars brighter than V = 10. We estimate a heavy element content of 20 +/- 7M(circle plus) for K2-232 b, which is consistent with standard models of giant planet formation. The bright host star of K2-232 b makes this system a well-suited target for detailed follow-up observations that will aid in the study of the atmospheres and orbital evolution of giant planets at moderate separations from their host stars.