Sources of uncertainties in the s-process in massive stars: convection and reaction rates

Abstract

Current models of s-nucleosynthesis in massive stars ($M\sim 15M_{\odot }$ to $\sim 30M_{\odot }$) are able to reproduce some main features of the abundance distributions of heavy isotopes in the solar system, at least in the $A\sim 60-90$ mass range. The efficiency of the process and the above specified mass range for the s-nuclei are still heavily uncertain due to both nuclear reaction rates and stellar models uncertainties. A series of s-process simulations with stellar models in the $15-30M_{\odot }$ (mass at ZAMS) and metallicity $Z=0.02$ mass have been performed to analyse the impact of the overshooting model used on the s-process yields. As in a previous exploratory work performed with stellar models having $M_{ZAMS}=25M_{\odot }$ and $Z=0.02$, enhancements factors in the range 2-5 are found in the final s-process efficiency when overshooting is inserted in the models.

4 pages, 2 figures, Proceedings of the ''Catania workshop on nuclear and neutrino astrophysics''