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| Paper: |
The Cool Algol BD+05 706 |
| Volume: |
154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop |
| Page: |
1644 |
| Authors: |
Torres, Guillermo; Neuhauser, Ralph; Wichmann, Rainer |
| Abstract: |
In the course of a spectroscopic follow-up program of X-ray selected sources from the ROSAT All Sky Survey, we have discovered an Algol-type binary in which both components are cool giants. The very few objects of this class that are known have been referred to as ``cool Algols''. We have solved for a double-lined spectroscopic orbit yielding minimum masses of M_A = 2.481 +/- 0.023 M_sun and M_B = 0.515 +/- 0.011 Msun, with a corresponding mass ratio of q ~0.21. The geometry of the system and other arguments suggest that the binary is very likely to be eclipsing. The rotation of the primary and secondary would appear to be synchronized with the orbital motion, with measured v sin i values of 22 and 31 km s^{-1}, respectively. We argue that the system is probably semi-detached, and we discuss its general properties compared to other objects of its class, including a correlation between the mass of the hotter, detached components and their effective temperature, as well as a trend between mass and orbital period. BD +05\arcdeg706 is likely to be the result of Case B mass transfer, with the hotter star (the mass gainer) located near the base of the giant branch. |
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