HD 32918 : Ultraviolet spectrum and optical behaviour.
Abstract
The first ultraviolet observations of HD 32918, a southern member of the FK Comae class, are presented. The observations were taken with the IUE satellite at two phases of the optical light curve, with simultaneous photometric coverage over more than one cycle in order to monitor the activity state of the star. The star shows very strong UV emission lines from the chromosphere and transition zone (TZ), similarly to other objects of the same class. Strong variations are seen in the high temperature lines (N V, Si IV, C IV) within one cycle. Similarly to what Bianchi et al.(1985) found for FK Comae, the Mg II (1) emission varies by a large factor on long time-scales (several months).
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1986
- Bibcode:
- 1986A&A...164...31G
- Keywords:
-
- Giant Stars;
- Late Stars;
- Southern Sky;
- Stellar Spectra;
- Ultraviolet Astronomy;
- Visible Spectrum;
- Electron Density (Concentration);
- Emission Spectra;
- High Resolution;
- Iue;
- Light Curve;
- Line Spectra;
- Magnesium;
- Stellar Rotation;
- Ultraviolet Spectra;
- Astrophysics