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arXiv 2204.03034astro-ph.SR
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~（12）C（α，γ）~（16）O反应速率的不确定性对中低质量恒星演化的影响

The impact of the uncertainties in the 12C(α,γ)16O reaction rate on the evolution of low- to intermediate-mass stars

Ben T. Pepper, A. G. Istrate, A. D. Romero, S. O. Kepler

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15 pages, 15 figures, 1 table
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摘要：

恒星演化计算中最大的不确定性之一是所考虑的反应速率的准确性。12 C（alpha，gamma）16 O反应对于中低质量恒星的研究特别重要，因为它决定了核心中最终的C/O比，而核心的C/O比又影响着白矮星的冷却演化。因此，有必要研究迄今为止对白矮星及其祖先的计算如何受到12 C（α，γ）16 O反应速率的不确定性的影响。在这项工作中，我们使用MESA代码计算完全进化的序列，初始质量在0.90 <= Mi/Msun <= 3.05的范围内。我们考虑不同的采用反应速率，从文献中获得，以及在其不确定性的极端限制。正如预期的那样，我们发现在核心氦燃烧阶段之前，恒星的演化没有变化。然而，随后的阶段都受到所考虑的反应速率的不确定性的影响。特别是，我们发现在核心氦燃烧阶段的对流核心质量的差异，这可能会影响亚矮星的脉动特性，在渐近巨星分支的热脉冲的数量和最终的氧丰度之间的趋势在核心和残留的白矮星的祖质量。

英文摘要：

One of the largest uncertainties in stellar evolutionary computations is the accuracy of the considered reaction rates. The 12C(alpha,gamma)16O reaction is particularly important for the study of low- and intermediate-mass stars as it determines the final C/O ratio in the core which influences the white dwarf cooling evolution. Thus, there is a need for a study of how the computations of white dwarfs and their progenitors that are made to date may be affected by the uncertainties of the 12C(alpha,gamma)16O reaction rates. In this work we compute fully evolutionary sequences using the MESA code with initial masses in the range of 0.90 <= Mi/Msun <= 3.05. We consider different adopted reaction rates, obtained from the literature, as well as the extreme limits within their uncertainties. As expected, we find that previous to the core helium burning stage there are no changes to the evolution of the stars. However, the subsequent stages are all affected by the uncertainties of the considered reaction rate. In particular, we find differences to the convective core mass during the core helium burning stage which may affect pulsation properties of subdwarfs, the number of thermal pulses during the asymptotic giant branch and trends between final oxygen abundance in the core and the progenitor masses of the remnant white dwarfs.

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