A Survey of Chromospherically Active Stars
Abstract
Photometric and/or spectroscopic observations have been obtained of 52 late-type stars which are suspected or known to be chromospherically active. Although not all types of observations were obtained for each star, these observations include all-sky BVRI Johnson photometry, ultraviolet spectrograms, low-dispersion blue-wavelength spectrograms, and high-dispersion red-wavelength spectrograms. From the spectroscopic observations v sin i's, radial velocities, and the appearance of the Ca II H and K emission lines have been determined as well as the H-alpha line. The photometric observations indicate that chromospherically active stars have V - R and V - I color excesses. Such excesses will affect the surface fluxes determined with the surface brightness-color relationship. On the other hand all-sky BVRI photometry appears to be an excellent way to identify chromospherically active stars. A small group of moderately rapidly rotating, possibly single G8-K2 giants has been found. These stars have very modest chromospheric activity and so are not FK comae stars. A number of other unusual chromospherically active stars are identified.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- February 1986
- DOI:
- 10.1086/191097
- Bibcode:
- 1986ApJS...60..551F
- Keywords:
-
- Chromosphere;
- Late Stars;
- Stellar Activity;
- Stellar Spectrophotometry;
- Astronomical Catalogs;
- Calcium;
- Emission Spectra;
- Giant Stars;
- H Alpha Line;
- Radial Velocity;
- Stellar Magnitude;
- Stellar Rotation;
- Ubv Spectra;
- Astronomy;
- CA II EMISSION;
- STARS: CHROMOSPHERES;
- STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 9746;
- STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 17144;
- STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 27536;
- STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 31993;
- STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 34198;
- STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 203251;
- ULTRAVIOLET: SPECTRA