HAT-P-55b: A Hot Jupiter Transiting a Sun-Like Star11Based on observations obtained with the Hungarian-made Automated Telescope Network. Based in part on radial velocities obtained with the SOPHIE spectrograph mounted on the 1.93-m telescope at Observatoire de Haute-Provence, France. Based in part on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland,

Abstract

We report the discovery of a new transiting extrasolar planet, HAT-P-55b. The planet orbits a V = 13.207 ± 0.039 sun-like star with a mass of 1.013 ± 0.037 M⊙, a radius of 1.011 ± 0.036 R⊙, and a metallicity of -0.03 ± 0.08. The planet itself is a typical hot Jupiter with a period of 3.5852467 ± 0.0000064 days, a mass of 0.582 ± 0.056 MJ and a radius of 1.182 ± 0.055 RJ. This discovery adds to the increasing sample of transiting planets with measured bulk densities, which is needed to put constraints on models of planetary structure and formation theories.