H alpha Observations of Early-Type Stars
Abstract
Results are presented of a first session of a program run at the Catania Astrophysical Observatory to study and monitor the H-alpha emission from early-type stars, and the properties of their mass loss are determined. Twelve early-type supergiants in the Cygnus region were observed repeatedly in 1988 July. From these observations, evidence is found for short-term variability of the mass-loss rate. Also, a comparison with literature data reveals strong long-term variations for some of the stars. In addition, simplified models were developed to describe the H-alpha profile resulting from the combination of photospheric absorption with emission and scattering in the wind. By fitting the observed profiles with the models, the mass-loss rates and the velocity fields are determined for all stars with accuracies generally better than 25 percent.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1992
- DOI:
- 10.1086/171418
- Bibcode:
- 1992ApJ...392..201S
- Keywords:
-
- Early Stars;
- H Alpha Line;
- Stellar Mass;
- Stellar Models;
- Supergiant Stars;
- Charge Coupled Devices;
- Emission Spectra;
- Stellar Winds;
- Astrophysics;
- STARS: EARLY-TYPE;
- STARS: EMISSION-LINE;
- BE;
- LINE: PROFILES;
- STARS: MASS LOSS;
- STARS: SUPERGIANTS