Higher mass loss rates for Wolf-Rayet stars?
Abstract
Calculations with a recently developed non-LTE code for realistic semiempirical models of Wolf-Rayet atmospheres revealed that, for effective temperatures below approximately 60 kK, the dominant ion in the radio-emitting region is not He(2+), as usually assumed, but He(+). Hence, for those Wolf-Rayet stars having effective temperatures below the quoted threshold, previous interpretations of the radio observations are not adequate. The inferred mass loss rates must be enhanced by up to a factor of 2.7, to take into account the lower free-free emissivity of He(+). Assuming all Wolf-Rayet stars to be cooler than the critical temperature, the corrected mean mass loss rate of the essentially distance-limited sample of Wolf-Rayet stars published by Abbott et al. (1986) becomes 0.00004 solar masses/yr.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1986
- Bibcode:
- 1986A&A...166L..11S
- Keywords:
-
- Stellar Atmospheres;
- Stellar Mass Ejection;
- Wolf-Rayet Stars;
- Atmospheric Models;
- Helium Ions;
- Nonequilibrium Thermodynamics;
- Radio Emission;
- Stellar Temperature;
- Astrophysics