The extended main-sequence turnoff region (eMSTO) shown as a common feature of young massive cluster (YMCs) in the Magellanic Clouds. Here we report the UV-optical colour-magnitude diagrams of four Large and Small Magellanic Cloud YMCs, NGC 330, NGC 1805, NGC 1818, and NGC 2164, based on high-resolution Hubble Space Telescope observations. We found that they all exhibit eMSTOs, which cannot be explained by stellar rotation alone. Adopting an age spread of 35–50 Myr can relax this diffculty. We suggest that stars in these clusters may be characterised by different ages and rotations, but the origin of the age spread remains unclear.
|Number of pages||5|
|Journal||Memorie della Società Astronomica Italiana = Journal of the Italian Astronomical Society|
|Publication status||Published - 2018|
- global clusters: individual: NGC 330, NGC 1805, NGC 1818, NGC 2164
- Hertzsprung-Russell and C-M diagrams
- Magellanic Clouds