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

TL;DR

This paper investigates how uncertainties in stellar convection modeling and nuclear reaction rates affect the s-process nucleosynthesis yields in massive stars, highlighting the impact of overshooting on element production.

Contribution

It provides a systematic analysis of the influence of overshooting and reaction rate uncertainties on s-process yields in massive stars between 15 and 30 solar masses.

Findings

Overshooting increases s-process efficiency by factors of 2-5.

Uncertainties in nuclear reaction rates significantly affect s-process predictions.

Stellar model variations impact the production of heavy isotopes in the 60-90 mass range.

Abstract

Current models of s-nucleosynthesis in massive stars ($M\sim15 M_{\odot}$ to $\sim 30 M_{\odot}$) 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 $15-30 M_{\odot}$ (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 $M_{ZAMS}=25 M_{\odot}$ 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.