Department of Physics, University of Basel, 4056 Basel, Switzerland.
Rep Prog Phys. 2013 Jun;76(6):066201. doi: 10.1088/0034-4885/76/6/066201. Epub 2013 May 10.
A small number of naturally occurring, proton-rich nuclides (the p-nuclei) cannot be made in the s- and r-processes. Their origin is not well understood. Massive stars can produce p-nuclei through photodisintegration of pre-existing intermediate and heavy nuclei. This so-called γ-process requires high stellar plasma temperatures and occurs mainly in explosive O/Ne burning during a core-collapse supernova. Although the γ-process in massive stars has been successful in producing a large range of p-nuclei, significant deficiencies remain. An increasing number of processes and sites has been studied in recent years in search of viable alternatives replacing or supplementing the massive star models. A large number of unstable nuclei, however, with only theoretically predicted reaction rates are included in the reaction network and thus the nuclear input may also bear considerable uncertainties. The current status of astrophysical models, nuclear input and observational constraints is reviewed. After an overview of currently discussed models, the focus is on the possibility to better constrain those models through different means. Meteoritic data not only provide the actual isotopic abundances of the p-nuclei but can also put constraints on the possible contribution of proton-rich nucleosynthesis. The main part of the review focuses on the nuclear uncertainties involved in the determination of the astrophysical reaction rates required for the extended reaction networks used in nucleosynthesis studies. Experimental approaches are discussed together with their necessary connection to theory, which is especially pronounced for reactions with intermediate and heavy nuclei in explosive nuclear burning, even close to stability.
少量天然存在的、富含质子的核素（p-核素）无法通过 s 过程和 r 过程产生。它们的起源尚未得到很好的理解。大质量恒星可以通过预存在的中间核和重核的光致蜕变来产生 p-核素。这种所谓的γ过程需要高恒星等离子体温度，主要发生在核心坍缩超新星的爆炸 O/Ne 燃烧过程中。虽然大质量恒星中的γ过程成功地产生了大量的 p-核素，但仍存在显著的缺陷。近年来，人们研究了越来越多的过程和地点，以寻找可行的替代方案来替代或补充大质量恒星模型。然而，大量的不稳定核素，尽管只有理论预测的反应速率被包含在反应网络中，因此核输入也可能带有相当大的不确定性。本文回顾了天体物理模型、核输入和观测约束的现状。在概述了目前讨论的模型之后，重点关注了通过不同手段更好地约束这些模型的可能性。陨石数据不仅提供了 p-核素的实际同位素丰度，还可以限制富含质子的核合成的可能贡献。综述的主要部分集中在确定用于核合成研究的扩展反应网络所需的天体物理反应率所涉及的核不确定性上。讨论了实验方法及其与理论的必要联系，对于爆炸核燃烧中中间核和重核的反应，这种联系尤为明显，甚至接近稳定性。
