On the Contribution of Ne-22 to the Synthesis of Fe-54 and Ni-58 in Thermonuclear Supernovae

The white dwarf explosion model accounts fairly well for the global characteristics of type Ia supernovae. There are, however, several problems concerning the dynamics of the burning front (deflagration or detonation regime), initial conditions and nucleosynthesis, that still deserve attention. In particular, the overproduction of neutron-rich nuclides such as Fe-54 and Ni-58, due to electron captures and to the neutron excess trapped in Ne-22 nuclei, still poses a major problem. In this paper we examine the possibilities for Ne-22 to migrate towards the central regions of the star and we show that if the white dwarf has had enough time to solidify, the contribution of Ne-22 to the neutron excess becomes negligible.