Relaxation Oscillations in Red-Giant Envelopes and the Symbiotic Stars
Abstract
The spectrum of a symbiotic star consists of an M-type absorption spectrum, a B-type shell spectrum and nebula emission lines, the relative contributions of these three components varying with time. The light curves of the symbiotic stars vary with a semi-regular period typically 200-800 days while larger eruptions occur on a timescale of 3.5 years. Some suggestions which have been advanced to explain the combination spectrum, variability and eruptive behaviour of the symbiotic stars are: (a) the symbiotic stars are binaries consisting of a hot and cool component. (b) the symbiotic stars consist of a single hot star surrounded by a large optically thick envelope giving the appearance of a hot continuum with the absorption spectrum of a cool star superimposed on it. (c) the symbiotic stars are single stars surrounded by a shock wave heated chromosphere. Although some of the symbiotic stars are undoubtedly binaries (for example, T Coronae Borealis), observatienal evidence suggests that others may be explained by hypothesis (c) above. The calculations described below provide an explanation of the symbiotic stars in conjunction with hypothesis (c).
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- October 1973
- DOI:
- 10.1017/S1323358000013552
- Bibcode:
- 1973PASA....2..198W