Supernova Nucleosynthesis in Massive Stars

Abstract

Presupernova models and nucleosynthesis in massive stars are reviewd in the context of supernovae. First, presupernova evolutionary models of massive stars toward the onset of collapse from 13 to 70 M. stars in the main-sequence stage are presented. It is stressed that silicon ("Si") shell burning is the key point to determine the final size of the iron core. As the result, we obtain the iron core ranges from 1.2 to 1.9 M. for 13-70 M. stars. Silicon-rich layers and the boundary between "Si" and oxygen-rich layers are neutronized during "Si" shell burning. The s-process during core helium burning is investigated in detail for whole massive stars. It is found that the weak component of the s-process is well overproduced compared with the solar system s-nuclei.