On the outer atmospheres of hybrid stars.
Abstract
The authors discuss a variety of ultraviolet observations of four hybrid atmosphere stars, objects which exhibit both cold winds and high-temperature (transition-region) emission. New IUE data confirm that the K3 II stars ι Aur and θ Her are hybrid stars. In addition γ Aql (K3 II) is found to be another hybrid object. The analysis of the emission lines indicates that at ≡105K, the pressure is between 10-2 and 10-3 that in the solar atmosphere at the same temperature. A corona with average temperature up to ≡5×105K could be accommodated. The observed line widths indicate that turbulent pressure is important. Very deep exposures of the Mg II emission lines in α TrA show that wind absorption is visible at velocities up to 180 km s-1 relative to the photosphere.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1985
- DOI:
- 10.1086/163476
- Bibcode:
- 1985ApJ...296..576H
- Keywords:
-
- Iue;
- Late Stars;
- Line Spectra;
- Stellar Composition;
- Stellar Envelopes;
- Stellar Mass Ejection;
- Abundance;
- Chromosphere;
- Lyman Alpha Radiation;
- Photosphere;
- Stellar Coronas;
- Stellar Winds;
- Astrophysics