| Title: |
Detection of a tertiary brown dwarf companion in the sdB-type eclipsing binary HS 0705+6700 |
| Authors: |
Qian, S., Zhu, L., Zola, S., Liao, W., Liu, L., Li, L., Winiarski, M., Kuligowska, E., Kreiner, J. |
| Publication Year: |
2009 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
HS 0705+6700 is a short-period (P=2.3 hours), close binary containing a hot sdB-type primary and a fully convective secondary. We have monitored this eclipsing binary for more than 2 years and as a result, 32 times of light minimum were obtained. Based on our new eclipse times together with these compiled from the literature, it is discovered that the O-C curve of HS 0705+6700 shows a cyclic variation with a period of 7.15 years and a semiamplitude of 92.4 s. The periodic change was analyzed for the light-travel time effect that may be due to the presence of a tertiary companion. The mass of the third body is determined to be M3 sin i = 0.0377 (+/-0.0043) Msun when a total mass of 0.617 Msun for HS 0705+6700 is adopted. For orbital inclinations i >= 32.8, the mass of the tertiary component would be below the stable hydrogen-burning limit of M3~0.072 Msun, and thus it would be a brown dwarf. The third body is orbiting the sdB-type binary at a distance shorter than 3.6 astronomical units (AU). HS 0705+6700 was formed through the evolution of a common envelope after the primary becomes a red giant. The detection of a sub-stellar companion in HS 0705+6700 system at this distance from the binary could give some constraints on stellar evolution in such systems and the interactions between red giants and their companions.
Comment: 10 pages, 3 figures To be published in Astrophysical Journal |
| Document Type: |
Working Paper |
| DOI: |
10.1088/0004-637X/695/2/L163 |
| Access URL: |
http://arxiv.org/abs/0903.1357 |
| Accession Number: |
edsarx.0903.1357 |
| Database: |
arXiv |
