ИСТИНА

Stellar populations in Galactic globular clusters (GGCs) exhibit specific dissimilarities as compared to those in open clusters. These are the manifestations of so-called multiple stellar populations in monometallic GGCs, which are not observed in other environments, neither in open clusters nor in the field. We focus on stellar collisions, an unexplored factor which could at least be one of the key contributors to these dissimilarities. The stellar collisions do occur in the densest part of GGCs but are of much lower probability in open clusters or improbable at all in the field. We draw attention and argue that the collisional blues stragglers observed in GGCs are just the top of the iceberg of main sequence stars modified via collisions and accumulated in GGCs during the cluster lifetime. We consider the expected key impact of stellar collisions on the characteristics of the modified stars in GGCs and (2) discuss the observed effects compatible with this process