Young star clusters in the Large Magellanic Cloud: NGC 1805 and 1818
Santiago, B. X.; Tanvir, N. R.; Gilmore, G. F.; Johnson, R. A.; Hurley, J.; Beaulieu, S. F.; Elson, R. A. W.
United Kingdom, Brazil
Abstract
We present colour-magnitude diagrams for two rich (~104Msolar) Large Magellanic Cloud star clusters with ages ~107yr, constructed from optical and near-infrared data obtained with the Hubble Space Telescope. These data are part of an HST project to study LMC clusters with a range of ages. In this paper we investigate the massive star content of the young clusters, and determine the cluster ages and metallicities, paying particular attention to Be-star and blue-straggler populations and evidence of age spreads. We compare our data with detailed stellar-population simulations to investigate the turn-off structure of ~25Myr stellar systems, highlighting the complexity of the blue-straggler phenomenon.