Building Blue Stragglers with Stellar Collisions

TL;DR

This paper models the evolution of stellar collision products in clusters, revealing they are brighter than normal stars but not fully mixed, challenging previous assumptions about their composition.

Contribution

It introduces a more realistic model for stellar collision products that accounts for partial mixing, improving upon simplified previous prescriptions.

Findings

Collision products are brighter than normal main sequence stars of the same mass.

They are less blue than models assuming full mixing during collision.

The study provides more accurate evolutionary tracks for collision products.

Abstract

The evolution of stellar collision products in cluster simulations has usually been modelled using simplified prescriptions. Such prescriptions either replace the collision product with an (evolved) main sequence star, or assume that the collision product was completely mixed during the collision. It is known from hydrodynamical simulations of stellar collisions that collision products are not completely mixed, however. We have calculated the evolution of stellar collision products and find that they are brighter than normal main sequence stars of the same mass, but not as blue as models that assume that the collision product was fully mixed during the collision.