What causes blue stragglers in globular clusters?

Question

Alice Andrews · Accepted Answer

It is thought that blue stragglers are caused by colliding stars.

On the Hertzsprung Russell diagram, stars in globular clusters exhibit a characteristic pattern that is not followed by blue stragglers because of their excessive size. The most likely explanation is that they are the result of binary star collisions, as blue stragglers are typically found in the denser regions of clusters where stars are more likely to collide because they are formed when two stars collide.

Henry Asbill · Answer

undefined The existence of blue stragglers, which appear too young and massive compared to their neighbors, is attributed to two main processes: 1. **Stellar Collisions and Mergers**: In the dense environments of globular clusters, stars are more likely to come close to each other or even collide. When lower-mass stars collide or merge, they can form a more massive star, which can have a higher temperature and luminosity, making it appear as a blue straggler. This phenomenon is intriguing because all stars in a cluster are generally expected to have formed around the same time, meaning they should have similar ages and evolve in a predictable way.