TERZAN-7 - A YOUNG METAL-RICH GLOBULAR-CLUSTER IN THE MILKY-WAY

The first extensive CCD color-magnitude diagram for the metal-rich galactic globular cluster Terzan 7 is presented. All age indicators derived from this diagram suggest that the cluster is young, about 70% of the age of 47 Tuc, which has similar metallicity. A rich population of blue straggler stars is also found in this cluster. With Terzan 7, the anomaly of young globular clusters is thus extended to cover almost the entire range of galactic globular cluster metallicities. Several possibilities for the origin of young galactic globular clusters are discussed.