Gamma Draconis (K5 III) is the first single, normal late K giant located on the red side of the coronal ``dividing line'' known to show conclusive evidence for both hot ( ~ 10(5) K) transition \ region (TR) and coronal (> 10(6) K) plasma. We present HST GHRS ultraviolet spectra of gamma Dra obtained on 1995 July 20 and 1991 April 6/18. These observations include spectra obtained at low, medium, and echelle resolution that provide a full set of chromospheric and TR emission line fluxes and profiles. These are combined with ROSAT PSPC observations to measure the TR and coronal properties, such as emission measure distribution, electron density, and nonthermal velocity fields, of this star. The high temperature emissions of gamma Dra are compared to those of a sample of hybrid-chromosphere bright giants and supergiants. This work is supported by Space Telescope Science Institute grant GO-06068.01-94A and NASA grants NAG5-1792 and NAGW-4529 to the University of Colorado.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1995