SIT-VIDICON Surface Photometry of Globular Clusters in the Magellanic Clouds

Extract

The globular clusters in the Large Magellanic Cloud offer an unique possibility for the study of their spatial structures. Their ages show a very wide range from 6·10⁷ to >5·10⁹ years which is unknown for their galactic counterparts. The latter ones are all very old and therefore dynamically relaxed systems, whereas the young globular clusters of the Magellanic Clouds (age <10⁸ years) have still preserved the dynamical state with which they were formed (Geyer et al. 1979). Furthermore, these young globulars show in their Hertzsprung-Russell diagram morphology the massive and luminous stars still on the main sequence with only a few evolved red supergiants. As in general the luminosity of the individual stars depends on their evolutionary state, the total mass to total luminosity ratio of a stellar cluster represents also its evolutionary state.