大样本恒星演化研究组知识库

Metallicity is the first parameter to influence the horizontal branch morphology of globular clusters. It has been found, however, that some other parameters may also play an important role in affecting the morphology. While the nature of these other important parameters remains unclear, they are believed to be correlated with the mass loss during the red giant stages, from which the horizontal branch stars have descended. Unfortunately, the mass loss during the red giant stages of stellar evolution are poorly understood at present. In this talk, we investigate the physical consequences of tidally-enhanced stellar winds during the evolution of binary stars on enhancing the mass loss of red giant primaries, with accompanying effects for the horizontal branch morphology of globular clusters. In a binary system, the stellar wind of the red giant primary star may be largely enhanced by its companion star. Different separation of the binary system, however, will lead to a different mass loss rate of the primary star. We found that red, blue, and extreme horizontal branch stars are all produced under the effects of tidally-enhanced stellar wind without any additional assumptions on the mass loss dispersion. Furthermore, the horizontal branch morphology is found to be insensitive to the tidal enhancement parameter, B.