Stellar β−-decay Rate of 63Ni and Its Impact on the s-process Nucleosynthesis in Massive Stars
The β ^− -decay rate of ^63 Ni, an important branching point, affects the subsequent nucleosynthesis in the weak component of the slow-neutron capture process (weak s -process). To evaluate the impact of the uncertainties of stellar lifetime of ^63 Ni on abundances, we calculate the contribution to...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adc1be |
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| Summary: | The β ^− -decay rate of ^63 Ni, an important branching point, affects the subsequent nucleosynthesis in the weak component of the slow-neutron capture process (weak s -process). To evaluate the impact of the uncertainties of stellar lifetime of ^63 Ni on abundances, we calculate the contribution to β ^− -decay rates from its excited states using the large-scale shell model with various interactions and also explore the atomic effects in the highly ionized plasma. In the core He burning stage and the shell C burning stage of massive stars, our new rates can be larger than those from K. Takahashi & K. Yokoi by up to a factor of 4 and 6, respectively. We evaluate the impact of the stellar decay rates of ^63 Ni on the nucleosynthesis of A = 60 ∼ 90 in a star with an initial mass of 25 M _⊙ and solar metallicity. We find that the new rates can lead to abundance changes of ^64 Ni, ^63 Cu, ^65 Cu, ^64 Zn, ^66 Zn, ^67 Zn, and ^68 Zn by up to 18%, 14%, 7%, 98%, 16%, 15%, and 13%, respectively, after the shell C burning stage at the Lagrangian mass coordinate M _r = 2 M _⊙ . The enhancement of the decay rate of ^63 Ni increases the weak s -process efficiency of nuclei after ^65 Cu. |
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| ISSN: | 1538-4357 |