Long‐Period Objects in the Extrasolar Planetary Systems 47 Ursae Majoris and 14 Herculis

The possible existence of additional long-period planetary-mass objects inthe extrasolar planetary systems 47 UMa and 14 Her is investigated. We combineall available radial-velocity data on these stars, spanning up to 18 years. Forthe 47 UMa system, we show that while a second planet improves the fit to allavailable data, there is still substantial ambiguity as to the orbitalparameters of the proposed planetary companion 47 UMa c. We also present newobservations which clearly support a long-period companion in the 14 Hersystem. With a period of 6906+/-70 days, 14 Her c may be in a 4:1 resonancewith the inner planet. We also present revised orbital solutions for 7previously known planets incorporating recent additional data obtained with the2.7m Harlan J. Smith Telescope at McDonald Observatory.Comment: Accepted for publication in Ap