SIMBAD references

The β^–-decay rate of ⁶³Ni, 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 ⁶³Ni 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 ⁶³Ni 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 ⁶⁴Ni, ⁶³Cu, ⁶⁵Cu, ⁶⁴Zn, ⁶⁶Zn, ⁶⁷Zn, and ⁶⁸Zn 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 = 2M_⊙. The enhancement of the decay rate of ⁶³Ni increases the weak s-process efficiency of nuclei after ⁶⁵Cu.