EUVE Observations of the Hyades Giants
Abstract
We describe EUVE and ROSAT observations of the Hyades K0 III giants theta1 (vB 71 = HR1411) and gamma (vB 28 = HR1346) Tau. We also discuss ASCA observations of theta1Tau. The coronal activity of these "clump" giants is intermediate between that of the Sun and of high activity stars such as RS CVn systems. There is no evidence for significant short or long term variability up to several years. Modeling of the individual and combined spectra suggest that these two X-ray and EUV-bright Hyades giants resemble in their activity levels another clump giant, beta Cet, with a peak in the emission measure distribution near log T approx. 6.8, reminiscent of the Capella emission measure "bump."
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- September 1998
- Bibcode:
- 1998STIN...0291600S
- Keywords:
-
- Coronas;
- Eclipsing Binary Stars;
- Extreme Ultraviolet Radiation;
- X Rays;
- Clumps;
- Extreme Ultraviolet Explorer Satellite;
- Rosat Mission;
- Sun;
- Variability;
- Geophysics