Impact of Stellar structure on Core-collapse Supernovae and their Ejecta

核心坍缩超新星（CCSN）是恒星演化的直接探测器，也是重元素的主要产生源。在过去的十年中，我们对CCSN机制的理解取得了重大进展，特别是认识到CCSN问题涉及许多物理输入的复杂相互作用，而这些物理输入只能在三维（3D）模拟中得到充分考虑。3D模拟的数量，包括足够的现实物理，已经完成的仍然很少，模拟通常是不足的。最近的观测调查大大增加了观测到的CCSN的数量，并确定了许多前超新星恒星，在爆炸的特征和细节之间建立了更直接的关系。该项目将在蓝水系统上使用最先进的CCSN代码Chimera来调查CCSN祖星的恒星质量范围，以了解前超新星结构的变化如何影响爆炸结果。模拟将从祖先恒星开始，这些恒星的质量范围从最轻的恒星到可能爆炸的最重的恒星。祖星模型将来自由大爆炸的原始气体形成的第一代恒星，因为存在一类仅被第一代超新星的喷射物污染的第二代恒星，这为测量单个CCSN的喷射产物提供了独特的机会。这一选择与之前专注于富金属恒星的研究形成了重要对比。该项目将在2年内以1度分辨率计算5次3D模拟。这超过了目前任何自一致的全物理CCSN模拟的分辨率。该项目更广泛的影响包括本地和访问学生（研究生和本科生）和博士后的参与，提供天体物理学和高性能计算方面的培训，我们的学生和博士后将这些培训带到后来在学术界和工业界的工作中。该计划还将经常就超新星相关主题进行公开讲座，以增进公众的了解。

Core-collapse supernovae (CCSN) are direct probes of stellar evolution and the dominant producers of heavy elements. Significant advancement in our understanding of the CCSN mechanism has occurred in the last decade, highlighted by the understanding that the CCSN problem involves the complex interaction of many physical inputs that can only be fully considered in three-dimensional (3D) simulations. The number of 3D simulations, which include sufficient realistic physics, that have been completed is still small and the simulations are generally under-resolved. Recent observational surveys have greatly increased the number of well observed CCSN and identified many of the pre-supernova stars, establishing a more direct relationship between the characteristics and the details of the explosion.This project will survey the range of the stellar mass of CCSN progenitors using the state-of-the-art CCSN code Chimera on the Blue Waters system to understand how the variations in pre-supernova structure affect the explosive outcomes. The simulations will begin from progenitor stars that span the range of stellar masses from the lightest to heaviest stars that might explode. The progenitor star models will be from the first generation of stars formed from the primordial gas of the Big Bang as there exists a class of second-generation stars contaminated by only the ejecta of first-generation supernovae that offer a unique opportunity to measure the ejected products of individual CCSN. This choice offers an important contrast to prior studies which have focused on metal-rich stars. The project will compute five 3D simulations over the course of 2 years with 1-degree resolution. This surpasses the resolution of any current self-consistent, full-physics CCSN simulation.The broader impacts of the project include the engagement of local and visiting students (graduate and undergraduate) and post-docs, providing training in both astrophysics and high-performance computing that our students and post-docs carry with them to later jobs in academia and industry. The project will also make frequent public lectures on supernova-related topics to enhance public understanding.