WASP-37b: A 1.8<i>M</i>_JEXOPLANET TRANSITING A METAL-POOR STAR

Abstract

We report on the discovery of WASP-37b, a transiting hot Jupiter orbiting an mv = 12.7 G2-type dwarf, with a period of 3.577469 ± 0.000011 d, transit epoch T0 = 2455338.6188 ± 0.0006 (HJD; dates throughout the paper are given in Coordinated Universal Time (UTC)), and a transit duration 0.1304-0.0017 +0.0018 d. The planetary companion has a mass Mp = 1.80 ± 0.17 MJ and radius R p = 1.16-0.06 +0.07 RJ, yielding a mean density of 1.15-0.15 +0.12 ρJ. From a spectral analysis, we find that the host star has M* = 0.925 ± 0.120M⊙, R* = 1.003 ± 0.053 R⊙, Teff = 5800 ± 150 K, and [Fe/H] = -0.40 ± 0.12. WASP-37 is therefore one of the lowest metallicity stars to host a transiting planet