The branchings of the main s-process: their sensitivity to α-induced reactions on 13C and 22Ne and to the uncertainties of the nuclear network
The branchings of the main s-process: their sensitivity to α-induced reactions on 13C and 22Ne and to the uncertainties of the nuclear network
复制标题
主要 s 过程的分支：它们对 13C 和 22Ne 上 α 诱导反应以及核网络不确定性的敏感性
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
R. deBoer
中科院分区：
文献类型：
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作者：
S. Bisterzo;R. Gallino;F. Kaeppeler;M. Wiescher;G. Imbriani;O. Straniero;S. Cristallo;Joachim Goerres;R. deBoer
本文详细分析了慢中子俘获过程的主要成分，它是90 A208核的一半的共辐射。我们研究了低质量渐近巨星分支（AGB）星中两种中子源的不确定性的影响：13 C（α，n）16 O反应，在脉冲间隔期间（kT <$8keV）辐射释放中子，22 Ne（α，n）25 Mg反应，在对流热脉冲（TP）期间部分激活。我们把我们的注意力集中在分支点，主要影响丰度的s-唯一的同位素。在我们的AGB模型中，13 C在脉冲间隔期间完全被辐射消耗。在这种情况下，我们发现，目前的不确定性与13 C（α，n）16 O反应只有微量的影响，只有核。另一方面，该速率的降低可能会增加脉间结束时的残留（或未燃烧）13 C的量：在这种情况下，残留13 C在由随后的TP提供动力的对流区中以较高的温度燃烧。22 Ne（α，n）25 Mg反应产生的中子爆发对路径沿着的分支有很大的影响，即使22 Ne（α，n）25 Mg反应率变化2倍，在太阳和核的不确定性范围内，也能再现90 A ≤ 204的纯s同位素的分布。提高几种关键放射性核素的β衰变率和中子捕获率将有助于全面了解太阳的主要成分。
This paper provides a detailed analysis of the main component of the slow neutron capture process(thes-process),whichaccountsforthesolarabundances ofhalfofthenucleiwith90 A 208. We examine the impact of the uncertainties of the two neutron sources operating in low-mass asymptotic giant branch (AGB) stars: the 13 C(α ,n ) 16 O reaction, which releases neutrons radiatively during interpulse periods (kT ∼ 8keV), and the 22 Ne(α ,n ) 25 Mg reaction, partially activated during the convective thermal pulses (TPs). We focus our attention on the branching points that mainly influence the abundance of s-only isotopes. In our AGB models, the 13 C is fully consumed radiatively during interpulse. In this case, we find that the present uncertainty associated with the 13 C(α,n) 16 O reaction has marginal effects ons-only nuclei. On the other hand, a reduction of this rate may increase the amount of residual (or unburned) 13 C at theend of theinterpulse: inthiscondition, the residual 13 Cisburned at higher temperature in the convective zone powered by the following TP. The neutron burst produced by the 22 Ne(α, n) 25 Mgreactionhas majoreffectsonthebranches along thes-path. Thecontributions ofs-only isotopes with 90 A ≤ 204 are reproduced within solar and nuclear uncertainties, even if the 22 Ne(α ,n ) 25 Mg rate is varied by a factor of 2. Improved β-decay and neutron capture rates of a few key radioactive nuclides would help to attain a comprehensive understanding of the solar main component.