Explosive nucleosynthesis in carbon deflagration models of Type I supernovae

There is increasing evidence that Type I supernovae (SN I) are the main producers of iron-peak elements in the Galaxy. In addition, observations of SN I also indicate the existence of appreciable amounts of intermediate elements like O, Mg, Si, S, and Ca in the outer layers of the exploding star. In an earlier paper it was shown that such an abundance pattern can be produced by carbon deflagration models of accreting carbon-oxygen white dwarfs in binary systems or stars on the asymptotic giant branch (AGB) which ignite central carbon burning explosively. In the present study, explosive nucleosynthesis results of those carbon deflagration supernovae are presented in detail. Special emphasis is given to the discussion of burning conditions and corresponding nucleosynthesis products, and the nuclear uncertainties which govern the amount of electron captures in the central part of the core. The latter gives constraints on the isotopic composition of the iron peak elements. The overproduction of Fe-54 + Ni-58 is still occurring. Assuming that SN I which contributed to the abundances in the solar system originated from white dwarfs with a metallicity range Z/solar-Z = 0.1-1, might remove this overproduction. This would allow for SN I to be the major contributors of Fe-group nuclei in galactic nucleosynthesis.