Photometry of southern globular clusters. - V. Photographic photometry of faint stars in omega Centauri.
Abstract
Photographic photometry obtained by the 3.9-m Anglo-Australian Telescope of approximately 300 faint stars in the globular cluster Omega Centauri is presented. The color-magnitude diagram was obtained from prime-focus plates measured with an iris photometer and calibrated by a faint photoelectric sequence. The main sequence turn-off point on the diagram is found to lie significantly below a V magnitude of 18, which is about 3.8 mag below the horizontal branch, however the value probably does not imply an exceptionally large age for the cluster. The spread in color observed at the top of the main sequence is noted to be compatible with the spread in heavy element abundance deduced from previous studies of the evolved stars, however does not establish the existence of a primordial abundance spread and is also compatible with a negligible intrinsic scatter in color. Future studies capable of resolving the problem of primordial abundance variations and the age of the cluster are indicated.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 1981
- DOI:
- 10.1093/mnras/195.1.15
- Bibcode:
- 1981MNRAS.195...15C
- Keywords:
-
- Abundance;
- Globular Clusters;
- Main Sequence Stars;
- Stellar Luminosity;
- Stellar Magnitude;
- Stellar Spectrophotometry;
- Color-Magnitude Diagram;
- Giant Stars;
- Heavy Elements;
- Hertzsprung-Russell Diagram;
- Lyra Constellation;
- Metallic Stars;
- Stellar Evolution;
- Astronomy;
- C-M Diagrams:Globular Clusters;
- Faint Stars:Photometry;
- Globular Clusters:Metal Content;
- Globular Clusters:Photometry