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

TL;DR

This paper reports the discovery of two Jupiter-mass exoplanets with highly eccentric orbits around evolved, metal-rich stars, using radial velocity measurements from the Lick and Keck surveys.

Contribution

It presents the detection of two new exoplanets orbiting evolved, metal-rich stars, highlighting the correlation between stellar metallicity and planet characteristics.

Findings

Both stars are metal-rich and evolved, with planets in highly eccentric orbits.

The planets have minimum masses of 4.4 and 0.68 Jupiter masses.

Orbital periods are 2.71 and 1.366 years, respectively.

Abstract

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_star = 1.3 M_sun) and are very metal rich ([Fe/H] > +0.3). We describe our methods for measuring the stars' radial velocity variations and photometric stability.