8th p-process workshop 2024

Convective-Reactive Nucleosynthesis in O-C Shell Mergers

16 Oct 2024, 14:50

10m

Oral presentation Afternoon session

Speaker

Mr Joshua Issa (University of Victoria)

Description

O-C shell mergers in massive stars have been proposed as a potential site for the production of p-process isotopes. These mergers provide a convective-reactive environment where the timescales for the nucleosynthesis of C-shell ashes such as ${}^{20}\mathrm{Ne}$ and convective mixing of species are of the same order. However, the nucleosynthetic pathways of these convective-reactive processes remain largely unexplored. In this study, we use the $15M_{\odot }$, $Z=0.02$ model from the NuGrid stellar data set II (Ritter et al., 2018) to create a detailed post-processed model of an O-C shell merger event. Three preliminary experiments were conducted by varying the reaction rates of ${}^{20}\mathrm{Ne}(\gamma ,\mathrm{p}{)}^{16}\mathrm{O}$, the $(\gamma ,\mathrm{p})$ rates for the odd-Z isotopes ${}^{31}\mathrm{P}$, ${}^{35}\mathrm{Cl}$, ${}^{39}\mathrm{K}$, ${}^{45}\mathrm{Sc}$, and all $(\mathrm{p},\gamma )$ rates by a factor of 10 up and down from their default values. The results show that altering the ${}^{20}\mathrm{Ne}(\gamma ,\mathrm{p}{)}^{16}\mathrm{O}$ rate has the strongest effect on the production of p-nuclei, notably ${}^{115}\mathrm{Sn}$, ${}^{138}\mathrm{La}$, ${}^{162}\mathrm{Er}$, ${}^{168}\mathrm{Yb}$, and ${}^{180}\mathrm{Ta}$. The other two experiments show a smaller impact on all isotopes. We will present the results of a full multizone Monte Carlo analysis of the impact from varying all reaction rates.

Presentation materials

budapest-nucleosynthesis-joshissa-slides.pdf

budapest-nucleosynthesis-joshissa-slides.pptx