An Evolutionary Considerations for V228 from 47 Tuc

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. The initial parameters for the evolutionary model are as follow: $M_{1,i} = 0.88 M_\odot$, $M_{2,i} = 0.85 M_\odot$, $P_i=1.35$days, $f_1$=0.05, $f_2$=4.65 and Z=0.006 ([Fe/H]=--0.67). 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. The less massive component have a small helium core of mass 0.12--0.17$M_\odot$ and exchange mass in the nuclear time scale.

Source: arXiv:0812.5051v1 - http://arxiv.org/abs/0812.5051v1 PDF: https://arxiv.org/pdf/0812.5051v1 Original Link: http://arxiv.org/abs/0812.5051v1