Two New Candidate Planets in Eccentric Orbits

Doppler measurements of two G–type main–sequence stars, HD210277 and HD168443, reveal Keplerian variations that imply the presence of companions with masses (M sin i ) of 1.28 and 5.04 MJUP and orbital periods of 437 d and 58 d, respectively. The orbits have large eccentricities of e=0.45 and e=0.54, respectively. All 9 known extrasolar planet candidates with a=0.2–2.5 AU have orbital eccentricities greater than 0.1, higher than that of Jupiter (e=0.05). Eccentric orbits may result from gravitational perturbations imposed by other orbiting planets or stars, by passing stars in the dense star-forming cluster, or by the protoplanetary disk. Based on published studies and our near-IR adaptive optics images, HD210277 appears to be a single star. However, HD168443 exhibits a long–term velocity trend consistent with a close stellar companion, as yet undetected directly. Subject headings: planetary systems – stars: individual (HD210277, HD168443, HD114762) Based on observations obtained at the W.M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology, and based on observations obtained at Lick Observatory which is operated by the University of California. Department of Physics and Astronomy, San Francisco State University, San Francisco, CA, USA 94132 and Department of Astronomy, University of California, Berkeley, CA USA 94720 Anglo–Australian Observatory, PO Box 296, Epping, NSW, 1710, Australia UCO/Lick Observatory, University of California at Santa Cruz, Santa Cruz, CA, USA 95064 Department of Astronomy, University of California, Berkeley, CA USA 94720