The winds of high luminosity late-type bright stars
Abstract
The occurrence and characteristics of the Fe II line asymmetries were studied to determine the radial dependence of the wind velocity for each star. The dependence of the Fe II profiles on spectral type and luminosity class and thus the variation of the velocity fields with stellar type was also investigated. This allows the generality of the results reported for alpha Ori by Carpenter (1984b) to be judged. In addition, new atomic data was used along with observations of the C II (UV 0.01) multiplet to estimate Ne in the stellar winds. Measures of relative Fe II fluxes can be used in a probability-of-escape model to determine the opacity and hydrogen column density versus height in the chromosphere of each star. Finally, analysis of the fluorescent Fe II lines (pumped by Ly alpha) near 2507 A will yield estimates of the intrinsic stellar Ly alpha flux that cannot be measured directly because of interstellar and circumstellar absorption. One important goal of the effort was to acquire high resolution spectra of the whole 2300 to 3200 A region of 13 luminous K and M stars as a data base that will be enormously valuable in planning observations with the Hubble Space Telescope High Resolution Spectrograph. It is also proposed to follow up the recent discovery of significant variations in the Fe II chromospheric emission line profiles from the M-giant Gamma Cru for the purpose of determining the underlying cause of the variations.
- Publication:
-
Final Report
- Pub Date:
- 1989
- Bibcode:
- 1989gsfc.reptQ....S
- Keywords:
-
- Chromosphere;
- K Stars;
- Late Stars;
- M Stars;
- Stellar Envelopes;
- Stellar Luminosity;
- Stellar Winds;
- Wind Velocity;
- Asymmetry;
- Fine Structure;
- Fluorescence;
- High Resolution;
- Hubble Space Telescope;
- Hydrogen;
- Spectrographs;
- Velocity Distribution;
- Astrophysics