Type Ia Supernova Progenitor Star Critical Accretion Rate Of Metal Abundance

A carbon-oxygen white dwarf may explode as Type Ia supernova by accreting matter from its company via either Roche lobe overflow or wind. We show the situation and development about Type Ia supernova, especially a various of progenitor models and explosion models. The most favoured model among various progenitor models is the single degenerate Chandrasekhar mass model, but there exists a critical accretion rate for the progenitor system. In this thesis, we study the relation between the critical accretion rate and the metallicity via AGB stars approach. The result indicates that the critical accretion rate is affected not only by the hydrogen mass fraction and the core mass, but also by the metallicity, though the effect of the metallicity is smaller than that of the core mass. However, our result might be useful for the binary population synthesis calculation about Type Ia supernova birth rate and at least could give a correction for previous results. For a given core mass, the luminosity of AGB stars is dispersal - a larger initial mass results in a larger luminosity, which is different from the previous argument that the luminosity is unique for a given core mass. We also try to give a new definition about the AGB stars. We may refer TPAGB stars as homology AGB (HAGB) stars and the second ignition of hydrogen is an appropriate criterion of the HAGB, since after the second ignition of hydrogen, AGB stars have similar properties and structures: a degenerate CO core covered by double thin burning shells.