Ultraviolet observations of stellar coronae : early results from HST.
Abstract
The first GHRS spectra of two very different late-type giant stars - Capella and Gamma Dra are reported. Capella is a 104 day period binary system consisting of two stars (G9 III and GO III) each of which shows bright emission lines formed in solar-like transition region and coronae. By contrast, Gamma Dra is a hybrid-chromosphere star with very weak emission lines from high-temperature plasma. Low-dispersion spectra of these stars covering the 1160 to 1717 A spectral range show unresolved emission lines from neutral species through N V. The very different surface fluxes detected in the spectra of these stars suggest different types of heating mechanisms.
- Publication:
-
Memorie della Societa Astronomica Italiana
- Pub Date:
- 1992
- Bibcode:
- 1992MmSAI..63..577L
- Keywords:
-
- Giant Stars;
- Late Stars;
- Spectrographs;
- Stellar Coronas;
- Ultraviolet Astronomy;
- Cool Stars;
- Extreme Ultraviolet Radiation;
- High Resolution;
- Line Spectra;
- Astrophysics