Radiative transfer in dust clouds. II. Circumstellar dust shells around early M giants and supergiants.
Abstract
Models derived from a solution of the equation of radiative transfer through dust shells are given for a sample of 27 stars whose spectral types range from M0 to M4 and have significant infrared excess. The models, which consist of a star in a spherically symmetric circumstellar dust shell (CDS), are compared with available observational data. It is found that all CDSs can be modeled with an n(r) varies with r to the -2 power density distribution, in keeping with steady outflow at a constant velocity. For the three stars Alpha-Ori, Mu-Cep and TV Gem, the temperature T1 of the hottest grains is 1000 K, while for 12 others 500 K yields a better fit. The Alpha-Ori model presented is consistent with most IR size measurements extant. Intensity profiles are given for several models, and the bright rim of radiation expected at all IR wavelengths at the inner edge of the dust shell is noted.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 1982
- DOI:
- 10.1093/mnras/200.2.197
- Bibcode:
- 1982MNRAS.200..197R
- Keywords:
-
- Early Stars;
- M Stars;
- Radiative Transfer;
- Stellar Envelopes;
- Stellar Models;
- Supergiant Stars;
- Dust;
- Giant Stars;
- Stellar Spectra;
- Stellar Temperature;
- Temperature Distribution;
- Astrophysics