EPIC 219388192b—An Inhabitant of the Brown Dwarf Desert in the Ruprecht 147 Open Cluster

摘要: We report the discovery of EPIC 219388192b, a transiting brown dwarf in 5.3 day orbit around member star Ruprecht 147, oldest nearby open cluster association, which was photometrically monitored by K2 during its Campaign 7. combine time-series data with ground-based adaptive optics imaging and high-resolution spectroscopy to rule out false positive scenarios determine main parameters system. 219388192b has radius R-b= 0.937 +/- 0.032 R-Jup mass M-b= 36.84 0.97 M-Jup, yielding mean density 59.6 7.6 g cm(- 3). The host is nearly solar twin M-star = 1.01 0.04 Me, R-star 0.03 R-circle dot, effective temperature T-eff 5850 85 K, iron abundance [Fe/ H]. 0.08 dex. Its age, spectroscopic distance, reddening are consistent those corroborating membership. first mature precise determinations mass, radius, serves as benchmark for evolutionary models substellar regime.