Search for beta Cephei stars south of declination -20 . I. Incidence of light variability among early B giants and subgiants - summer objects.
Abstract
A list has been compiled of all Bright Star Catalogue objects spectroscopically similar to beta Cephei variables, and located south of declination -20 arcdeg. Nearly one thousand differential uvby observations have been obtained of sixty-eight of these stars that fall within the right ascension range from about 4 h 10 10 h 15 m. Over 14 (but less than 24) stars turn out to be variable in b by more than 0.020 mag, while 21 have been found to be constant to within 0.010 mag or better. The upper limit for the number hitherto undiscovered beta Cephei variables with the b amplitude exceeding 0.020 mag could be estimated as equal to four. One star, HD 64722=HR 3088 (B1.5 IV), shows beta Cephei-type light variation in a very short period of 0.1160+/-0.0003 d, with apparently stable b lightamplitude equal to 0.027+/-0.002 mag. In addition, out of a total of sixty four non-beta Cephei strip comparison stars, over 12 (but less than 21) prove to be variable in b by 0.020 mag or more, and 23 are constant. Of the former, at least two stars are periodic, viz., lambda Columbae varies in a period equal to 0.640+/-0.002 d, with the b magnitude of 0.30+/-0.003 mag, while for HD 74455=HR 3462 the period is found to be 0.563+/-0.001 d, and the b amplitude -0.037+/-0.002 mag. In both these cases the light variability is probably caused by proximity effects in a binary system.
- Publication:
-
Acta Astronomica
- Pub Date:
- 1977
- Bibcode:
- 1977AcA....27..365J
- Keywords:
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- Astronomical Photometry;
- B Stars;
- Giant Stars;
- Stellar Luminosity;
- Variable Stars;
- Southern Hemisphere;
- Standard Deviation;
- Stellar Magnitude;
- Tables (Data);
- Astronomy