Stellar surface phenomena: stellar rotation and the BY Draconis syndrome in the high-eccentricity binary BD+24/sup 0/692
The double-line spectroscopic binary (SB2) BD+24/sup 0/692 (sp. dK3) is found to be a BY Draconis variable, showing a light variation of approx.0.1 mag owing to spots on the rotating stellar surface. The rotation period, 6.82 days, differs markedly from the orbital period of 11.93 days. The discovery of high surface activity on essentially all dK--dM SB2 stars supports the hypothesis that rotation with v(equator)> or approx. =5 km s/sup -1/ is the underlying cause of the BY Dra syndrome. The two high-eccentricity BY Dra SB2 systems (BD+24/sup 0/692 and BY Dra itself) do not exhibit synchronism. An examination of the synchronization time from tidal effects implies that BY Dra is surprisingly young, in support of Vogt and Fekel's (Astrophys. J. 234, 958 (1979)) arguments that BY Dra is in the last stages of pre-main-sequence evolution.
- Research Organization:
- Ritter Observatory, University of Toledo, Toledo, Ohio 43606
- OSTI ID:
- 7096368
- Journal Information:
- Astron. J.; (United States), Journal Name: Astron. J.; (United States) Vol. 85:10; ISSN ANJOA
- Country of Publication:
- United States
- Language:
- English
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