Light variations of extreme galactic B- and A supergiants.
Abstract
Summary. Twelve extreme B- and A supergiants of the Southern Hemisphere were photometrically monitored in 1973 and 1974. The observations were carried out in a differential way in the uvby system. Eleven of these objects were found to be variable over medium and long time intervals. It was also found that the very extreme object HD 160529 exhibits small- amplitude light variations over a time scale of several hours, and there are, furthermore, indications that similar short term fluctuations are also present in HD 168607. The appreciable differences between the 1973 and 1974 yearly mean values indicate that the amplitudes over very long time intervals can be much bigger. All variations show the highest fluctuation in y and U - V, whereas only small or even no variations in b - y and V - b were found. Characteristic times of the variations in V were determined using a least squares method. These semi-periods range between 5 days and 100 days, and show an indication of being correlated with the absolute visual magnitude. Key words: supergiants photometric variations pulsation
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1977
- Bibcode:
- 1977A&A....57..361S
- Keywords:
-
- A Stars;
- B Stars;
- Light Curve;
- Stellar Luminosity;
- Supergiant Stars;
- Diurnal Variations;
- Spatial Distribution;
- Star Distribution;
- Astrophysics