Two Exoplanets Discovered at Keck Observatory

Authors :: Valenti, J. A.
Fischer, D. A.
Marcy, G. W.
Johnson, J. A.
Henry, G. W.
Wright, J. T.
Howard, A. W.
Giguere, M.
Isaacson, H.
Publication Year :: 2009
Abstract: We present two exoplanets detected at Keck Observatory. HD 179079 is a G5 subgiant that hosts a hot Neptune planet with Msini = 27.5 M_earth in a 14.48 d, low-eccentricity orbit. The stellar reflex velocity induced by this planet has a semiamplitude of K = 6.6 m/s. HD 73534 is a G5 subgiant with a Jupiter-like planet of Msini = 1.1 M_jup and K = 16 m/s in a nearly circular 4.85 yr orbit. Both stars are chromospherically inactive and metal-rich. We discuss a known, classical bias in measuring eccentricities for orbits with velocity semiamplitudes, K, comparable to the radial velocity uncertainties. For exoplanets with periods longer than 10 days, the observed exoplanet eccentricity distribution is nearly flat for large amplitude systems (K > 80 m/s), but rises linearly toward low eccentricity for lower amplitude systems (K > 20 m/s).<br />Comment: 8 figures, 6 tables, accepted, ApJ