The Age of Galactic Cluster NGC 188.
Abstract
The early evolution of lower main-sequence stars of Population I (composition parameters X = 0.67, Z = 0.03) is calculated on an IBM 7090 computer using the entirely automatic method of Larson and Demarque (1964). The agreement between theory and Sandage's color-maguitude diagram of NGC 188 is good and yields an age of 9- 10 X 10' years for that cluster. From another evolutionary track for X = 0 75 and Z = 0.01, the age of NGC 188 is estimated at 12 X 10' years, but it is found in this case that agreement with observation is not as satisfactory as for composition (X = 0 67, Z = 003).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1964
- DOI:
- 10.1086/147948
- Bibcode:
- 1964ApJ...140..544D