THE PAN-PACIFIC PLANET SEARCH. I. A GIANT PLANET ORBITING 7 CMa

Abstract

We introduce the Pan-Pacific Planet Search, a survey of 170 metal-rich Southern Hemisphere subgiants using the 3.9 m Anglo-Australian Telescope. We report the first discovery from this program, a giant planet orbiting 7 CMa (HD 47205) with a period of 763 +/- 17 days, eccentricity e = 0.14 +/- 0.06, and msin i = 2.6 +/- 0.6 M(Jup). The host star is a K giant with a mass of 1.5 +/- 0.3M(circle dot) and metallicity [Fe/H] = 0.21 +/- 0.10. The mass and period of 7 CMa b are typical of planets which have been found to orbit intermediate-mass stars (M(*) > 1.3M(circle dot)). Hipparcos photometry shows this star to be stable to 0.0004 mag on the radial-velocity period, giving confidence that this signal can be attributed to reflex motion caused by an orbiting planet.