The impact of selective mass loss on the age determination of star clusters

Dynamical models and observations of star cluster evolution show clear signs of mass segregation (in the sense that high-mass stars tend to be found towards the cluster center, and low-mass stars preferentially occupy the cluster outskirts). The low-mass stars in the cluster outskirts get stripped off more easily by interaction with the gravitational potential of their host galaxy. This alters the stellar mass function within the cluster, therefore changes its spectrophotometry, altering the cluster ages determined when the new spectrophotometry is compared to standard evolutionary synthesis models. These age changes can amount up to a factor of ten (in the most extreme cases).