Production of Lithium and Heavy Elements in AGB Stars Experiencing PIEs
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arXiv
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| Hauptverfasser: | , , , |
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| Format: | Preprint |
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2024
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| author | Choplin, A. Siess, L. Goriely, S. Martinet, S. |
| author_facet | Choplin, A. Siess, L. Goriely, S. Martinet, S. |
| contents | Asymptotic giant branch (AGB) stars can experience proton ingestion events (PIEs), leading to a rich nucleosynthesis. During a PIE, the intermediate neutron capture process (i-process) develops, leading to the production of trans-iron elements. It is also suggested that lithium is produced during these events. We investigate the production of lithium and trans-iron elements in AGB stars experiencing a PIE with $1<M_{\rm ini}/M_{\odot}< 3$ and $-3< \mathrm{[Fe/H]} <0$. We find that lithium is produced in all PIE models with surface abundances $3<$ A(Li) $<5$. The surface enrichment and overall AGB lithium yield increases with decreasing stellar mass. The lithium enrichment is accompanied by a production of $^{13}$C with $3<^{12}$C/$^{13}$C$<9$ at the surface just after the PIE. AGB stars experiencing PIE may be related to J-type carbon stars whose main features are excesses of lithium and $^{13}$C. In addition to Li and $^{13}$C, heavy elements (e.g., Sr, Ba, Eu, Pb) are significantly produced in low-metallicity stars up to [Fe/H]$\simeq-1$. The yields of our models are publicly available. Additionally, of interest to the Li nucleosynthesis, we provide an updated fitting formula for the $^{7}$Be($e^-,ν_e$)$^{7}$Li electron capture rate. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_12630 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Production of Lithium and Heavy Elements in AGB Stars Experiencing PIEs Choplin, A. Siess, L. Goriely, S. Martinet, S. Solar and Stellar Astrophysics Asymptotic giant branch (AGB) stars can experience proton ingestion events (PIEs), leading to a rich nucleosynthesis. During a PIE, the intermediate neutron capture process (i-process) develops, leading to the production of trans-iron elements. It is also suggested that lithium is produced during these events. We investigate the production of lithium and trans-iron elements in AGB stars experiencing a PIE with $1<M_{\rm ini}/M_{\odot}< 3$ and $-3< \mathrm{[Fe/H]} <0$. We find that lithium is produced in all PIE models with surface abundances $3<$ A(Li) $<5$. The surface enrichment and overall AGB lithium yield increases with decreasing stellar mass. The lithium enrichment is accompanied by a production of $^{13}$C with $3<^{12}$C/$^{13}$C$<9$ at the surface just after the PIE. AGB stars experiencing PIE may be related to J-type carbon stars whose main features are excesses of lithium and $^{13}$C. In addition to Li and $^{13}$C, heavy elements (e.g., Sr, Ba, Eu, Pb) are significantly produced in low-metallicity stars up to [Fe/H]$\simeq-1$. The yields of our models are publicly available. Additionally, of interest to the Li nucleosynthesis, we provide an updated fitting formula for the $^{7}$Be($e^-,ν_e$)$^{7}$Li electron capture rate. |
| title | Production of Lithium and Heavy Elements in AGB Stars Experiencing PIEs |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2410.12630 |