We present a new method to determine the age spread of resolved stellar populations in a starburst cluster. The method relies on a two-step process. In the first step, kinematic members of the cluster are identified based on multi-epoch astrometric monitoring. In the second step, a Bayesian analysis is carried out, comparing the observed photometric sequence of cluster members with sets of theoretical isochrones. When applying this methodology to optical and near-infrared high angular resolution Hubble Space Telescope (HST) and adaptive optics observations of the 5Myr old starburst cluster Westerlund1 and 2Myr old starburst cluster NGC3603YC, we derive upper limits for the age spreads of 0.4 and 0.1Myr, respectively. The results strongly suggest that star formation in these starburst clusters happened almost instantaneously.
- HertzsprungRussell and CM diagrams
- open clusters and associations: individual (Westerlund 1, NGC 3603 YC)
- stars: evolution
- stars: formation
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science