Bibliographic Details
| Title: |
2M1155-79 (= T Cha B): A Low-mass, Wide-separation Companion to the Nearby, 'Old' T Tauri Star T Cha |
| Authors: |
Kastner, Joel H., Thompson, E., Montez Jr., R., Murphy, S. J., Bessell, M. S., Sacco, G. G. |
| Publication Year: |
2012 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
The early-K star T Cha, a member of the relatively nearby (D ~ 100 pc) epsilon Cha Association, is a relatively "old" (age ~7 Myr) T Tauri star that is still sporadically accreting from an orbiting disk whose inner regions are evidently now being cleared by a close, substellar companion. We report the identification, via analysis of proper motions, serendipitous X-ray imaging spectroscopy, and followup optical spectroscopy, of a new member of the epsilon Cha Association that is very likely a low-mass companion to T Cha at a projected separation of ~38 kAU. The combined X-ray and optical spectroscopy data indicate that the companion, T Cha B (= 2M1155-79), is a weak-lined T Tauri star (wTTS) of spectral type M3 and age ~<10 Myr. The serendipitous X-ray (XMM-Newton) observation of T Cha B, which targeted T Cha, also yields serendipitous detections of two background wTTS in the Chamaeleon cloud complex, including one newly discovered, low-mass member of the Cha cloud pre-MS population. T Cha becomes the third prominent example of a nearby, "old" yet still actively accreting, K-type pre-MS star/disk system (the others being TW Hya and V4046 Sgr) to feature a low-mass companion at very large (12-40 kAU) separation, suggesting that such wide-separation companions may affect the conditions and timescales for planet formation around solar-mass stars.
Comment: 14 pages, 4 figures; to appear in The Astrophys. J. (Letters) |
| Document Type: |
Working Paper |
| DOI: |
10.1088/2041-8205/747/2/L23 |
| Access URL: |
http://arxiv.org/abs/1202.0262 |
| Accession Number: |
edsarx.1202.0262 |
| Database: |
arXiv |
