Impact of newly measured 26Al( n , p )26Mg and 26Al( n , a)23Na reaction rates on the nucleosynthesis of 26Al in stars
Impact of newly measured 26Al( n , p )26Mg and 26Al( n , a)23Na reaction rates on the nucleosynthesis of 26Al in stars
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新测量的 26Al( n , p )26Mg 和 26Al( n , a)23Na 反应速率对恒星中 26Al 核合成的影响
DOI：
10.1093/mnras/stad106
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发表时间：
2023
影响因子：
4.8
通讯作者：
Battino U
中科院分区：
文献类型：
--
作者：
Battino U
短寿命放射性核素26Al的宇宙产生对于我们理解恒星和星系的演化至关重要。然而，对产生 26 Al 的恒星位点的模拟仍然因显着的核不确定性而受到削弱。我们基于最近的n_TOF测量结合理论预测和先前在更高能量下的测量，重新评估了从0.01 GK到10 GK的26Al(n, p)26Mg和26Al(n, α)23Na基态反应性，并测试了它们对恒星核合成的影响。我们使用 Monash 核合成代码、NuGrid mppnp 代码和 FUNS 恒星演化代码计算了低质量和高质量恒星的核合成。我们的低质量恒星模型覆盖了 2–3 M⊙ 质量范围，金属丰度在 Z =0.01 和 0.02 之间，它们预测的 26Al/27Al 比率与 62 个陨石 SiC 颗粒进行了比较。对于大质量恒星，我们在 Z = 0.006 和 0.02 的两个 15 M⊙模型上测试了我们的反应性。新的反应性使低质量 AGB 星能够再现在 SiC 晶粒中测量的 26Al/27Al 比率的全范围。当采用我们速率的上限或下限时，在最高产量点，大质量恒星中最终的 26 Al 丰度变化为 2.4 倍。然而，巨大的不确定性在这两个大众政权中仍然发挥着重要作用。新的反应性明显影响低质量和高质量恒星的核合成，并使得星尘碳化硅颗粒和低质量恒星模型之间的比较得到全面改进。关于爆炸性核合成，未来的研究需要改善当前 T9∼0.3 和 2.5 之间的不确定性。
The cosmic production of the short-lived radioactive nuclide26Al is crucial for our understanding of the evolution of stars and galaxies. However, simulations of the stellar sites producing26Al are still weakened by significant nuclear uncertainties. We re-evaluate the26Al(n, p)26Mg, and26Al(n, α)23Na ground state reactivities from 0.01 GK to 10 GK, based on the recent n_TOF measurement combined with theoretical predictions and a previous measurement at higher energies, and test their impact on stellar nucleosynthesis. We computed the nucleosynthesis of low- and high-mass stars using the Monash nucleosynthesis code, the NuGrid mppnp code, and the FUNS stellar evolutionary code. Our low-mass stellar models cover the 2–3 M⊙mass range with metallicities betweenZ =0.01 and 0.02, their predicted26Al/27Al ratios are compared to 62 meteoritic SiC grains. For high-mass stars, we test our reactivities on two 15 M⊙models withZ =0.006 and 0.02. The new reactivities allow low-mass AGB stars to reproduce the full range of26Al/27Al ratios measured in SiC grains. The final26Al abundance in high-mass stars, at the point of highest production, varies by a factor of 2.4 when adopting the upper, or lower limit of our rates. However, stellar uncertainties still play an important role in both mass regimes. The new reactivities visibly impact both low- and high-mass stars nucleosynthesis and allow a general improvement in the comparison between stardust SiC grains and low-mass star models. Concerning explosive nucleosynthesis, an improvement of the current uncertainties between T9∼0.3 and 2.5 is needed for future studies.