Binary population synthesis for the core-degenerate scenario of type Ia supernova progenitors

The core-degenerate (CD) scenario has been suggested to be a possible progenitor model of type Ia supernovae (SNe Ia), in which a carbon-oxygen white dwarf (CO WD) merges with the hot CO core of a massive asymptotic giant branch (AGB) star during their common-envelope phase. However, the SN Ia birthrates for this scenario are still uncertain. We conducted a detailed investigation into the CD scenario and then gave the birthrates for this scenario using a detailed Monte Carlo binary population synthesis approach. We found that the delay times of SNe Ia from this scenario are ~70Myrs-1400Myrs, which means that the CD scenario contributes to young SN Ia populations. The Galactic SN Ia birthrates for this scenario are in the range of ~7.4*10^{-5} yr^{-1}-3.7*10^{-4}yr^{-1}, which roughly accounts for ~2-10% of all SNe Ia. This indicates that, under the assumptions made here, the CD scenario only contributes a small portion of all SNe Ia, which is not consistent with the results of Ilkov & Soker (2013).