Evolution of rotating binary stars

Abstract

A model for the evolution of rotating binary stars is presented. The evolution of a binary system consisting of a 9 and a 6 star is studied in the mass transfer phase Case A. Specific attention is focused on the differences between the evolutions with and without the effects of rotation. The results indicate that the effects of rotation prolong the lifetime of the primary, and causes its evolutionary track in the HR diagram to shift towards lower luminosity. The mass and the surface helium composition of the primary become lower and the orbital period of the system becomes significantly longer during the later stage of the evolution.