Spectra of the Brighter Variables in Globular Clusters.
Abstract
Spectrograms of 35 variables of high luminosity in 14 globular clusters were obtained at Mount Wilson with low dispersion. Membership in the clusters was tested by measures of radial velocity, which were compared with the velocities obtained at the Lick Observatory from the integrated light of the clusters. A tabulation of the stars according to period and physical characteristics indicates that the globular clusters contain, in addition to the RR Lyrae stars, several variables of four definite groups: short period (1-2 days), W Virginis, RV Tauri (with high luminosity), and irregular or semiregular variables (period 60-i 10 days). Cepheids, Mira stars, and semiregular variables (types M4-M6) are rare or absent. In gen- eral, the variables found in the clusters correspond to those of population II
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1949
- DOI:
- 10.1086/145190
- Bibcode:
- 1949ApJ...110..105J