A Chandra Search for Low-mass Companions of Late B Stars in Tr 16
Abstract
The cluster Tr 16 is included within the area of the large survey of the Carina region with Chandra (PI: Townsley). Stars later than B3 are not known to produce X-rays. On the other hand, low mass stars (later than mid-F spectral type) produce copious X-rays when they are young. We have developed a list of B3 to A0 stars in the young cluster Tr 16 which: 1.) are within 3' of Eta Car, 2.) have an appropriate V and B-V combination (including a range of +/- 0.1 in E(B-V), and 3.) have proper motions consistent with cluster membership. We have identified stars from this list which are X-ray sources on a 90 ksec Chandra image of Tr 16. Presumably the X-rays are produced by a low mass companion, at least in nearly all cases. This attribution is reinforced by the fact that the X-ray sources have higher median temperatures than O and early B sources. In addition, the spectral fits to 4 strongest sources produce temperatures typical of low-mass coronal sources. On this basis, 39% of the late B stars have low mass companions. Interpretation of this number depends on the completeness of the X-ray detections, however discussion of the low mass stars in Tr 16 indicates that stars which will be M stars on the main sequence are detected.
N. Evans acknowledges support from the Chandra X-ray Center NASA Contract NAS8-03060- Publication:
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American Astronomical Society Meeting Abstracts #217
- Pub Date:
- January 2011
- Bibcode:
- 2011AAS...21714426R