The variable shell star HR 5999 VII. The extended atmosphere of a Herbig AE star : chromospheric features.
Abstract
The IUE and ground-based spectroscopic observations of the nebular variable HR 5999 are discussed. Results show strong chromospheric emission lines in the spectra of this star. The emission measures of the high temperature lines suggest a low temperature gradient and large radiation losses for the transition region. The large energy loss points to the presence of convective motions in the surface layers of the star, which are probably a remnant of earlier phases in the evolution of the star. A correlation of emission line fluxes with rotation velocity indicates that dynamo magnetic fields play a major role in the transfer of energy from the convective region to the chromospheric and transition region of a star.
- Publication:
-
Third European IUE Conference
- Pub Date:
- June 1982
- Bibcode:
- 1982ESASP.176..113T
- Keywords:
-
- Astrophysics;
- Chromosphere;
- Emission Spectra;
- Shell Stars;
- Stellar Spectra;
- Variable Stars;
- Convective Heat Transfer;
- Iue;
- Stellar Magnetic Fields;
- Stellar Rotation;
- Stellar Temperature;
- Surface Layers;
- Temperature Gradients