The search for multiple populations in young and intermediate-age star clusters .
Abstract
Ancient Globular Clusters (GCs) are known to host multiple populations in the form of abundance spreads in light elements. Although common in old (>10 Gyr) GCs, these features have been thought for a long time to be absent in younger star clusters (<10 Gyr) with comparable masses. We started a photometric survey using the Hubble Space Telescope to search for multiple populations in massive star clusters of various ages in the Magellanic Clouds. The main goal of this survey is to constrain the age limit down to which star clusters are capable to form multiple populations. Therefore, the clusters included in our survey span a large range of ages (between 100 Myr and 10 Gyr) and have masses larger than 105 M⊙. We discovered for the first time the presence of multiple population in star clusters as young as 6-7 Gyr. Another common feature, which is not in agreement with a simple stellar population, is the extended main sequence turn-off observed in Magellanic Cloud clusters with ages less than ∼2 Gyr. We also present recent results on this topic and the connection of the extended main sequence turn-off feature to stellar rotation.
- Publication:
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Memorie della Societa Astronomica Italiana
- Pub Date:
- 2018
- Bibcode:
- 2018MmSAI..89...80N
- Keywords:
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- Hertzsprung-Russell and colour-magnitude diagrams;
- galaxies: star clusters;
- galaxies: individual: LMC;
- galaxies: individual: SMC;
- stars: abundances;
- stars: rotation