A Dedicated M Dwarf Planet Search Using The Hobby-Eberly Telescope
Abstract
We present the first results from our planet-search program using the 9.2 m Hobby-Eberly Telescope (HET) at McDonald Observatory to detect planets around M-type dwarf stars by means of high-precision radial velocity (RV) measurements. Although more than 100 extrasolar planets have been found around solar-type stars of spectral type F-K, there is only a single M dwarf (GJ 876) known to harbor a planetary system. With the current incompleteness of Doppler surveys with respect to M dwarfs, it is not yet possible to decide whether this is due to a fundamental difference in the formation history and overall frequency of planetary systems in the low-mass regime of the Hertzsprung-Russell diagram, or simply an observational bias. Our HET M dwarf survey plans to survey 100 M dwarfs in the next 3 to 4 years, with the primary goal being to answer this question. Here we present the results from the first year of the survey, which show that our routine RV precision for M dwarfs is 6 m s-1. We found that GJ 864 and GJ 913 are binary systems with as yet undetermined periods, while five out of 39 M dwarfs reveal a high RV scatter and represent candidates for having short-period planetary companions. For one of them, GJ 436 (rms=20.6 m s-1), we have already obtained follow-up observations, but no periodic signal is present in the RV data.
Based on data collected with the Hobby-Eberly Telescope, which is operated by McDonald Observatory on behalf of the University of Texas at Austin, Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.- Publication:
-
The Astronomical Journal
- Pub Date:
- December 2003
- DOI:
- 10.1086/379137
- arXiv:
- arXiv:astro-ph/0308477
- Bibcode:
- 2003AJ....126.3099E
- Keywords:
-
- Stars: Planetary Systems: General;
- Stars: Late-Type;
- Stars: Low-Mass;
- Brown Dwarfs;
- Techniques: Radial Velocities;
- Astrophysics
- E-Print:
- 12 pages, 14 figures, accepted for publication in the Astronomical Journal