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Extended main sequence turn-offs (eMSTOs) are a common feature in color-magnitude diagrams (CMDs) of young and intermediate-age star clusters in the Magellanic Clouds. The nature of eMSTOs is still debated. The most popular scenarios are extended star formation and ranges of stellar rotation rates. Here we study implications of a kink feature in the main sequence (MS) of young star clusters in the Large Magellanic Cloud (LMC). This kink shows up very clearly in new emph{Hubble Space Telescope} observations of the 700-Myr-old cluster NGC 1831, and is located below the region in the CMD where multiple or wide MSes, which are known to occur in young clusters and thought to be due to varying rotation rates, merge together into a single MS. The kink occurs at an initial stellar mass of $1.45 pm 0.02;M_{odot}$; we posit that it represents a lower limit to the mass below which the effects of rotation on the energy output of stars are rendered negligible at the metallicity of these clusters. Evaluating the positions of stars with this initial mass in CMDs of massive LMC star clusters with ages of $sim,$1.7 Gyr that feature wide eMSTOs, we find that such stars are located in a region where the eMSTO is already significantly wider than the MS below it. This strongly suggests that stellar rotation emph{cannot} fully explain the wide extent of eMSTOs in massive intermediate-age clusters in the Magellanic Clouds. A distribution of stellar ages still seems necessary to explain the eMSTO phenomenon.
We show that the extended main sequence turnoffs seen in intermediate age Large Magellanic Cloud (LMC) clusters, often attributed to age spreads of several hundred Myr, may be easily accounted for by variable stellar rotation in a coeval population.
Recent high-quality photometry of many star clusters in the Magellanic Clouds with ages of 1$,-,$2 Gyr revealed main sequence turnoffs (MSTOs) that are significantly wider than can be accounted for by a simple stellar population (SSP). Such extended
We use the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope (HST) to obtain deep, high resolution images of two intermediate-age star clusters in the Large Magellanic Cloud of relatively low mass ($approx$ $10^4$ $M_{odot}$) and signific
[Abridged] The stellar Initial Mass Function (IMF) suggests that sub-solar stars form in very large numbers. Most attractive places for catching low-mass star formation in the act are young stellar clusters and associations, still (half-)embedded in
We present color-magnitude diagram analysis of deep Hubble Space Telescope imaging of a mass-limited sample of 18 intermediate-age (1 - 2 Gyr old) star clusters in the Magellanic Clouds, including 8 clusters for which new data was obtained. We find t