A spectroscopic study of the close binary CG Cygni.
Abstract
Fifty spectrograms of the eclipsing close binary CG Cyg are examined. The component stars are classified as G9.5 V and K3 V, respectively. Indirect evidence for emission or circumstellar absorption of Balmer lines is discussed, each component is found to contribute Ca II H and K emission of nearly equal strength, and the Ca II emission is suggested to be of probable chromospheric origin. Respective rotation rates of about 58 and 70 km/s are obtained for the hotter and the cooler star, along with respective radii of 510,000 and 620,000 km, and a system mass ratio close to 1.0. It is concluded that the Ca II emission, variable Balmer lines, spectral types, approximate sizes, and mass ratio of this system provide a further link between the 'short-period' RS CVn-related binaries and the classical RS CVn systems.
- Publication:
-
The Astronomical Journal
- Pub Date:
- August 1979
- DOI:
- 10.1086/112531
- Bibcode:
- 1979AJ.....84.1218N
- Keywords:
-
- Cygnus Constellation;
- Eclipsing Binary Stars;
- Emission Spectra;
- Stellar Spectra;
- Stellar Spectrophotometry;
- Balmer Series;
- Calcium;
- H Lines;
- K Lines;
- Light Curve;
- Spectrum Analysis;
- Stellar Rotation;
- Astrophysics;
- Close Binaries:Rotation;
- Diameters:Eclipsing Binaries;
- Eclipsing Binaries:Spectroscopy