We announce the discovery of a twin of Jupiter orbiting the slightly metal-poor ([Fe/H] = - 0.1) nearby (d = 18 pc) G8 dwarf HD 154345. This planet has a minimum mass of 0.95 MJup and a 9.2 year, circular orbit with radius 4.2 AU. There is currently little or no evidence for other planets in the system, but smaller or exterior planets cannot yet be ruled out. We also detect a ~ 9 year activity cycle in this star photometrically and in chromospheric emission. We rule out activity cycles as the source of the radial velocity variations by comparison with other cycling late G dwarfs.Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. The Keck Observatory was made possible by the generous financial support of the W. M. Keck Foundation.
The Astrophysical Journal
- Pub Date:
- August 2008
- planetary systems;
- techniques: radial velocities;
- 15pp. ApJL. v2: Substantial additions, including 3 new authors, new photometry, activity measurements, and a discussion of activity cycles