eMSTOs in low mass clusters

The four clusters have ages between 1-2Gyr and two of them appear to host eMTSOs. The discovery of eMSTOs in such low mass clusters - more than 5 times less massive than the eMSTO clusters previously studied - suggests that mass is not the controlling factor in whether clusters host eMSTOs.

Additionally, the narrow extent of the eMSTO in the two older clusters (~2Gyr) is in agreement with predictions of the stellar rotation scenario, as lower mass stars are expected to be magnetically braked, meaning that their colour magnitude diagrams should be better reproduced by canonical simple stellar populations. We also performed a structural analysis on all the clusters and found that a large core radius is not a requisite for a cluster to exhibit an eMSTO.