Abstract:
Typical lifetime of an open cluster is rather short compared to the age of the Galaxy, but there exists a wide spread in the individual lifetimes. The observed age distribution of the clusters. Trumpler (1930) has classified open clusters on the basis of three parameters namely central concentration, range in brightness of clusters members, and the number of stars in clusters. Janes & Alder (1982) and Pandey & Mahra (1986) have obtained the lifetimes of clusters of different richness classes. Pandey, Bhatt & Mahra (1987) have also obtained the lifetimes of the open cluster as a function of their linear diameters. The linear diameters of open clusters vary considerably from 2 to 16 pc depending on the constitution of the cluster (Trumpler 1930).
