The Chromospheres of M Dwarf Stars.
Abstract
Single-component, homogeneous, quiescent semi-empirical model chromospheres are constructed, based upon high resolution, well-calibrated profiles of the Ca II K line in 3 dMe and 2 dM stars. The results of the atmospheric models inferred from the observed Ca II K line profiles reveal several systematic trends which characterize the chromospheres of M dwarf stars. In particular, high values of T min/Teff are deduced for the stars considered, thus indicating an unusually large degree of nonradiative heating present in the upper photospheres of M dwarf stars. Hence dissipation of mechanical energy is an important parameter in the control of the energy balance in the upper photospheres of M dwarf stars. The value of the lower chromospheric temperature gradient, dT/d log m, is similar for the M dwarf stars considered. Chromospheric K-line emission strength is most sensitive to the total amount of chromospheric material present within the approximate temperature range Tmin-6000K.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1980
- Bibcode:
- 1980PhDT.........5G
- Keywords:
-
- Physics: Astronomy and Astrophysics;
- Atmospheric Models;
- Chromosphere;
- Dwarf Stars;
- M Stars;
- Celestial Mechanics;
- Stars;
- Stellar Atmospheres;
- Astrophysics