The Pan-Pacific Planet Search. I. A Giant Planet Orbiting 7 CMa

TL;DR

This paper introduces the Pan-Pacific Planet Search and reports the discovery of a giant planet orbiting the star 7 CMa, demonstrating the survey's capability to find planets around intermediate-mass stars.

Contribution

First discovery from the Pan-Pacific Planet Search, identifying a giant planet around a metal-rich subgiant star, expanding knowledge of planet occurrence around such stars.

Findings

Discovered a giant planet with a 763-day period orbiting 7 CMa.

The planet has a minimum mass of 2.6 Jupiter masses.

Star's photometry confirms the planetary signal is not due to stellar variability.

Abstract

We introduce the Pan-Pacific Planet Search, a survey of 170 metal-rich Southern hemisphere subgiants using the 3.9m 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 m sin i=2.6+/-0.6 M_jup. The host star is a K giant with a mass of 1.5+/-0.3 M_sun 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*>1.3 M_sun). 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.