Deep ACS imaging of Intermediate-Age Star Clusters in the LMC: Clues to the Nature of Multiple Stellar Populations (Paul Goudfrooij, STScI)

For almost a century, the standard paradigm that globular clusters (GCs) consist of "simple" stellar populations has contributed enormously to our understanding of stellar evolution. However, this notion has had to face serious challenges over the last decade. One such challenge was that spectroscopic surveys showed that light elements such as C, N, O, F, and Na show large star-to-star abundance variations (often dubbed ``Na-O anticorrelations'') within all Galactic GCs studied to date in sufficient detail. However, the old age of Galactic GCs has precluded a clear picture of the time scales involved with this enrichment. In this talk I will present photometric and dynamical evidence for the presence of age ranges of 100-500 Myr among stars in massive intermediate-age GCs in the Magellanic Clouds. I will argue that this age range in such GCs is physically associated with the presence of the Na-O anticorrelations seen in Galactic GCs and illustrate the impact of this finding to understanding hitherto unexplained observational results.