Discovery of Seven T Tauri Stars and a Brown Dwarf Candidatein the Nearby TW Hydrae Association
Abstract
We report the discovery of five T Tauri star systems, two of which are resolved binaries, in the vicinity of the nearest known region of recent star formation: the TW Hydrae Association. The newly discovered systems display the same signatures of youth (namely high X-ray flux, large Li abundance, and strong chromospheric activity) and the same proper motion as the original five members. These similarities firmly establish the group as a bona fide T Tauri association, unique in its proximity to Earth and its complete isolation from any known molecular clouds. At an age of ~10 Myr and a distance of ~50 pc, the association members are excellent candidates for future studies of circumstellar disk dissipation and the formation of brown dwarfs and planets. Indeed, as an example, our speckle imaging revealed a faint, very likely companion 2" north of CD -33° 7795 (TWA 5). Its color and brightness suggest a spectral type of ~M8.5 which, at an age of ~107 yr, implies a mass ~20MJup.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1999
- DOI:
- 10.1086/311856
- arXiv:
- arXiv:astro-ph/9812189
- Bibcode:
- 1999ApJ...512L..63W
- Keywords:
-
- GALAXY: OPEN CLUSTERS AND ASSOCIATIONS: INDIVIDUAL: NAME: TW HYDRAE;
- STARS: LOW-MASS;
- BROWN DWARFS;
- STARS: PRE-MAIN-SEQUENCE;
- X-RAYS: STARS;
- Galaxy: Open Clusters and Associations: Individual: Name: TW Hydrae;
- Stars: Low-Mass;
- Brown Dwarfs;
- Stars: Pre-Main-Sequence;
- X-Rays: Stars;
- Astrophysics
- E-Print:
- 6 pages, 4 figures and 1 table. AAS LaTeX aas2pp4.sty. To be published in ApJ