Parent Stars of Extrasolar Planets. VII. New Abundance Analyses of 30 Systems

The results of new spectroscopic analyses of 30 stars with giant planetand/or brown dwarf companions are presented. Values for Teff and [Fe/H] areused in conjunction with Hipparcos data and Padova isochrones to derive masses,ages, and theoretical surface gravities. These new data are combined withspectroscopic and photometric metallicity estimates of other stars harboringplanets and published samples of F, G, and K dwarfs to compare several subsetsof planet bearing stars with similarly well-constrained control groups. Thedistribution of [Fe/H] values continues the trend uncovered in previous studiesin that stars hosting planetary companions have a higher mean value thanotherwise similar nearby stars. We also investigate the relationship betweenstellar mass and the presence of giant planets and find statistically marginalbut suggestive evidence of a decrease in the incidence of radial velocitycompanions orbiting relatively less massive stars. If confirmed with largersamples, this would represent a critical constraint to both planetary formationmodels as well as to estimates of the distribution of planetary systems in ourgalaxy.Comment: 27 pages, 13 figures. Accepted for publication in The Astronomical Journa