Back to Volume
Paper: Broad-Band Colour Evolution of Star Clusters.
Volume: 211, Massive Stellar Clusters
Page: 133
Authors: Girardi, L.
Abstract: We briefly review the main features in the broad-band colour evolution of star clusters, over the complete age interval from 107 to 1010 yr. The emphasis is in the problem of age-dating distant young clusters (<= 2 Gyr) from their integrated colours. It is shown that U-B and B-V are less sensitive to metallicity than colours involving red passbands, like V-I, at least up to ages of a few Gyr. Since U-B and B-V are determined by well-understood and well-populated evolutionary stages, they are also less affected by theoretical uncertainties and by the ubiquitous effect of stochastic colour dispersion. The latter effects become important for the V-K colour. Thus, we argue that U-B and B-V are, presently, the more suitable broad-band colours for age-dating distant clusters. For other potentially useful colours like V-R and V-I, empirical tests of their evolution are still missing.
Back to Volume