AGB星He壳层内重核素丰度分布

以13C（α，n）16O及22Ne（α，n）25Mg作为双脉冲中子源，对于星族Ⅰ低质量AGB星，采用无分叉s-过程反应通道，结合最新恒星演化的计算结果，在各物理参量合理取值范围内，计算了He壳层内重核素核合成。结果表明，随着脉冲数的增加，逐渐达到渐近丰度分布。渐近分布达到后，He壳层内s-元素的丰度仅与平均中予辐照量τ0有关。

The Heavy-nuclide Abundances in the He-Shell of the Asymptotic Giant Brauch Stars

In this paper, we present the nucleosynthesis calculations in the convective He-shell for the asymptotic giant branch (AGB). The main neutron source at the origin of s-process nucleosynthesis is assumed to be the reaction 13C(α,n)16O; a minor contribution derives also from the marginai activation of the reaction 22Ne(α,n) 25Mg at the end of each flash. We adopt a unbranched s-process network, and use standard models for the number of pulss that depends on the adopted value of effective neutron exposure τ0. After asymptotic abundances have been achieved, the distributions of s-nuclei can be simple characterized by τ0.