Chromospheres of M dwarf stars with incipient H-alpha emission.
Abstract
Observations are presented of H-alpha and Ca II resonance lines in 4 stars having H-alpha features which place them intermediately between the non-(e) and (e) classifications of dK/dM stars. There is considerable variety in the shape of the H-alpha line, presumably due in part to differences in rotation rates. As expected, the energy fluxes in the Ca II emission lines lie between those typical of non-(e) and (e) stars. There is some evidence (especially from the binary Gl 876A) that the energy fluxes in the Ca II and H-alpha emission lines do not vary from star to star according to a simple proportionality. An intriguing result is the apparent detection of spatially displaced chromospheric emission in Gl 907.1 and Gl 890.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- 1989
- DOI:
- 10.1017/S1323358000023158
- Bibcode:
- 1989PASA....8..132R
- Keywords:
-
- Chromosphere;
- Dwarf Stars;
- Emission Spectra;
- H Alpha Line;
- M Stars;
- Stellar Spectra;
- Binary Stars;
- K Stars;
- Metallicity;
- Stellar Models;
- Stellar Rotation;
- Astrophysics