Fourteen New Companions from the Keck and Lick Radial Velocity Survey Including Five Brown Dwarf Candidates
Abstract
We present radial velocities for 14 stars on the California and Carnegie Planet Search target list that reveal new companions. One star, HD 167665, was fit with a definitive Keplerian orbit leading to a minimum mass for the companion of 50.3 MJup at a separation from its host of ~5.5 AU. Incomplete or limited phase coverage for the remaining 13 stars prevents us from assigning to them unique orbital parameters. Instead, we fit their radial velocities with Keplerian orbits across a grid of fixed values for Msini and period P, and use the resulting χ2ν surface to place constraints on Msini, P, and semimajor axis a. This technique allowed us to restrict Msini below the brown dwarf-stellar mass boundary for an additional four companions (HD 150554, HD 8765, HD 72780, HD 74014). If the combined five companions are confirmed as brown dwarfs, these results would comprise the first major catch of such objects from our survey beyond ~3 AU.
Based on observations obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2007
- DOI:
- 10.1086/519066
- arXiv:
- arXiv:0704.3418
- Bibcode:
- 2007ApJ...665..744P
- Keywords:
-
- Stars: Binaries: Spectroscopic;
- Stars: Planetary Systems;
- Stars: Low-Mass;
- Brown Dwarfs;
- Techniques: Radial Velocities;
- Astrophysics
- E-Print:
- 29 pages, 14 figures, accepted to ApJ