Old, Rich, and Eccentric: Two Jovian Planets Orbiting Evolved Metal-Rich Stars

We present radial velocity measurements of two stars observed as part of the Lick Subgiants Planet Search and the Keck N2K survey. Variations in the radial velocities of both stars reveal the presence of Jupiter-mass exoplanets in highly eccentric orbits. HD 16175 is a G0 subgiant from the Lick Subgiants Planet Search, orbited by a planet having a minimum mass of 4.4 M_Jup, in an eccentric (e = 0.59), 2.71 yr orbit. HD 96167 is a G5 subgiant from the N2K (“Next 2000”) program at Keck Observatory, orbited by a planet having a minimum mass of 0.68 M_Jup, in an eccentric (e = 0.71), 1.366 yr orbit. Both stars are relatively massive (M_⋆ = 1.3 M_⊙) and are very metal rich ([Fe/H] > +0.3). We describe our methods for measuring the stars’ radial velocity variations and photometric stability.

Based on observations obtained at the Lick Observatory, which is operated by the University of California, and on observations obtained at the W. M. Keck Observatory, which is operated as a scientific partnership with the University of California, the California Institute of Technology, and the National Aeronautics and Space Administration. Keck Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Keck time has been granted by both NASA and the University of California.