An Eclipsing "Blue Straggler" V228 from 47 Tuc: Evolutionary Consideration

TL;DR

This study models binary star evolution to explain the origin of the eclipsing blue straggler V228 in 47 Tuc, highlighting the importance of orbital momentum loss in its formation.

Contribution

It presents a new evolutionary scenario for V228, showing how initial binary parameters lead to its current state through specific mass and momentum loss processes.

Findings

V228 likely originated from a low-mass main sequence accretor.

The system's evolution involves losing about 50% of orbital momentum.

Only 5% of the initial mass was lost during evolution.

Abstract

We perform evolutionary calculations of binary stars to find progenitors of system with parameters similar to the eclipsing binary system V228. We show that a V228 binary system may be formed starting with an initial binary system which has a low main sequence star as an accretor. We also show that the best fitting model implies loss of about 50 per cent of initial total orbital momentum but only 5 per cent of initial total mass.