Nucleosynthesis studies of the origins of heavy nuclei using diverse observables and modern computational methods

在自然界中观测到的最重元素的天体物理学起源的线索可以在大量的可观测物中找到。例如，我们的太阳揭示了它诞生的条件包含了由慢(s)和快(r)中子捕获过程合成的元素的痕迹，这是自然界中观测到的最重元素的原因。这些过程在太阳和恒星元素丰度的不同“峰”形式中有指纹。计算方法提供了一种从可观测到基础物理的现代方法。提出的工作将训练机器学习算法来识别r-process和s-process模式。然后，当面对恒星模式时，它可以提供对每个过程贡献的估计。以前，我们应用统计方法来寻找形成太阳r过程稀土峰（包含元素，如铕）所需的核质量，目前来源不确定。将我们预测的质量与实验室测量的质量进行比较，有助于了解稀土元素的天体物理生成。拟议的工作将在此基础上进行扩展，考虑其他统计方法，并以已知的导致其他太阳丰度峰值的原子核质量为目标。近年来，越来越多的观测数据被发现，比如首次观测到的双中子星合并（NSM） GW170817，引力波和光都被探测到了。这一事件的光提供了第一个直接证据，证明nsm至少合成了一些r过程元素。然而，NSM事件是否产生了最重的物质，如金和铀，以及合并是否解释了我们太阳系的重元素含量，仍然不清楚。拟议的工作将建立在先前的研究基础上，这些研究将从GW170817推断出的NSM频率与通过检查其他元素并结合未来的探测来解释太阳系中铕所需的预测频率进行比较。拟议的工作还将建立一个光曲线预测目录，当产生特定的同位素时，以帮助确定未来nsm中物种的存在。由于我们解释可观测结果的能力受到实验范围内和实验范围外物种的核性质的严重影响，这些研究将有助于指导未来的理论和实验研究计划。流体动力学模拟正在改进我们对爆炸事件的理解，如nsm和可能承载r过程的奇异磁旋转驱动超新星（mhd）。由于中微子相互作用对预测的核合成有重要影响，因此建议的工作将包括对mhd中中微子的磁相互作用的首次处理。因此，拟议的研究将协同跨学科的同步进展，以解决我们自己的宇宙起源的基本开放科学问题。

Clues to the astrophysical origins of the heaviest elements observed in nature can be identified in a multitude of observables. For instance, our Sun reveals that the conditions in which it was born contained traces of elements synthesized by the slow (s) and rapid (r) neutron capture processes, which are responsible for the heaviest elements observed in nature. These processes have fingerprints in the form of distinct "peaks" seen in solar and stellar elemental abundances. Computational methods provide a modern way to go backwards from observables to fundamental physics. The proposed work will train a machine learning algorithm to recognize r-process and s-process patterns. Then when confronted with stellar patterns, it can provide an estimate of the contributions of each process. Previously we applied statistical methods to find the nuclear mass required to form the solar r-process rare-earth peak (containing elements such as europium) which is presently of uncertain origin. Comparisons between our predicted masses and those measured in laboratories provided insights on the astrophysical production of rare-earth elements. Proposed work will expand upon this by considering alternative statistical methods and by targeting masses of nuclei known to be responsible for other solar abundance peaks. Access to additional observables has grown in recent years, evidenced by multi-messenger detections such as the first ever observed binary neutron star merger (NSM) GW170817, from which both the gravitational wave and light was detected. The light from this event provided the first direct evidence that NSMs synthesize at least some r-process elements. However, whether NSM events produce the heaviest species such as gold and uranium, and whether mergers explain the heavy element content of our Solar System, remains unclear. Proposed work will build on previous studies which compared the NSM frequency inferred from GW170817 to the predicted frequency needed to explain europium in the Solar System by examining other elements and incorporating future detections. Proposed work will also build a catalog of light curve predictions when specific isotopes are produced to help identify the presence of species in future NSMs. Since our ability to interpret observables is critically influenced by the nuclear properties of species both within and beyond experimental reach, these studies will serve to guide future theoretical and experimental research programs. Hydrodynamic simulations are refining our understanding of explosive events such NSMs and exotic magneto-rotationally driven supernovae (MHDs) which could host an r process. Since neutrino interactions critically influence the predicted nucleosynthesis, proposed work will include a first treatment of the magnetic interaction of neutrinos in MHDs. The proposed studies will therefore synergize simultaneous progress across disciplines to address the fundamental open science question of our own cosmic origins.