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According to standard infall-model of Galactic chemical evolution models, adopting the two sets of recently published nucleosynthesis yields of Type II supernova explosion (as parameters of our model A and model B respectively), we calculated the abundance evolution of oxygen in the solar neighborhood. Then we compared the predicted age-metallicity relationship and metallicity distribution of G-dwarfs with the observational data. Our results show that the yields from Nomoto et al. (1997a) is more suitable to explain the observed trend of oxygen in the solar neighborhood than that of Woosley & Weaver (1995).

We propose that the absence of the metal zero star, the first generation star (FGS), may be explained by the mechanism for metallicity enrichment of a star in the Galaxy based on the host Galaxy’s disk-star interactions. The mechanism involves an accreting of interstellar medium (ISM). The zero metal star may accrete a small amount of metal rich material of the ISM and polluted the star’s composition. We suggest here that the expected degree of the polluted relative average metallicity[Fe/H]of a star may be[Fe] ~ —4.5.