An Eccentric Hot Jupiter Orbiting the Subgiant HD 185269

Abstract

We report the detection of a Jupiter-mass planet in a 6.838 day orbit around the 1.28 Msolar subgiant HD 185269. The eccentricity of HD 185269b (e=0.30) is unusually large compared to other planets within 0.1 AU of their stars. Photometric observations demonstrate that the star is constant to +/-0.0001 mag on the radial velocity period, strengthening our interpretation of a planetary companion. This planet was detected as part of our radial velocity survey of evolved stars located on the subgiant branch of the H-R diagram-also known as the Hertzsprung gap. These stars, which have masses between 1.2 and 2.5 Msolar, play an important role in the investigation of the frequency of extrasolar planets as a function of stellar mass. Based on observations obtained at the Lick Observatory, which is operated by the University of California.