The Pan-Pacific Planet Search. VII. The Most Eccentric Planet Orbiting a Giant Star
Marshall, J. P.; Mustill, A. J.; Kane, Stephen R.; Butler, R. P.; Villaver, Eva; Wittenmyer, Robert A.; Horner, Jonathan; Jones, M. I.; Zhao, Jinglin; Jenkins, J. S.; Clark, Jake; Rojas, P. A. Pena
Australia, Chile, United States, Taiwan, Sweden, Spain
Abstract
Radial velocity observations from three instruments reveal the presence of a 4 MJup planet candidate orbiting the K giant HD 76920. HD 76920b has an orbital eccentricity of 0.856 ± 0.009, making it the most eccentric planet known to orbit an evolved star. There is no indication that HD 76920 has an unseen binary companion, suggesting a scattering event rather than Kozai oscillations as a probable culprit for the observed eccentricity. The candidate planet currently approaches to about four stellar radii from its host star, and is predicted to be engulfed on a ∼100 Myr timescale due to the combined effects of stellar evolution and tidal interactions.