The Effect of Enhanced Core Masses on the Observed Morphology of Young Clusters

In this chapter, we address a further generalisation of the methodology developed in Chapter 2 and applied to the cases of eclipsing binaries without pulsations in Chap. 4 and non-eclipsing binaries with pulsations in Chap. 5. This generalisation applies to young stellar clusters with a total of N members. We apply this generalised modelling to investigate the phenomenon of the extended main-sequence turn-off (eMSTO). Traditionally, the eMSTO has been explained by rapidly rotating stars or binaries and their interaction products, however, neither mechanism is capable of fully explaining the observations. Through our modelling of the two young massive clusters NGC 1850 and NGC 884, we demonstrate that internal mixing, as discussed throughout this monograph, is capable of explaining a large portion of the observed eMSTO phenomenon.