Simulating Core-collapse Supernovae: from the Central Engine to the Stellar Surface

大质量恒星，比如猎户座的参宿四，会以核心坍缩超新星的形式结束生命。这些强大的爆炸标志着一颗中子星的诞生，并将一波喷射物传播到星系中，其中包括大量新形成的化学元素。构成我们自己和地球的许多元素都是在过去的超新星爆炸中产生的。现代对超新星爆炸的理解强调了从新生的中子星逃逸出来的中微子加热的高度湍流的抛射物。该项目将研究这些爆炸及其抛射物，重点是i)决定新生中子星结构的核物理方面如何影响超新星爆炸，以及ii)超新星发展中的高度湍流、中微子驱动动力学如何影响爆炸产生的化学元素。这些任务将为理论核物理和计算物理的研究生提供良好的训练基础。研究人员和他们的学生将使用CHIMERA中微子辐射流体动力学代码对许多恒星质量的超新星爆炸进行二维和三维模拟。为了研究中子星核物理对爆炸的影响，将探索使用一系列核状态方程的模型。本研究将揭示核状态方程对超新星爆炸影响最大的物理状态。为了研究核心坍缩超新星的核合成，研究人员将利用后处理分析（通过示踪粒子和大型核反应网络）来探索一系列模型的完整核合成影响。这将通过在CHIMERA模拟中包含更大、更真实的核反应网络的额外模拟来促进。总之，这些模型有望提供迄今为止最真实的模拟核心坍缩超新星的元素和同位素产生。

Massive Stars, like Betelgeuse in the Constellation Orion, end their lives as a core-collapse supernova. These powerful explosions mark the birth of a neutron star and spread a wave of ejecta, including a wealth of newly-made chemical elements, into the galaxy. Many of the elements that make up ourselves and our planet were produced in past supernova explosions. The modern understanding of the supernova explosion highlights highly turbulent ejecta heated by neutrinos that are escaping from the newborn neutron star. This project will study these explosions and their ejecta with a focus on i) how the nuclear physics aspects that determine the structure of the newborn neutron star influences the supernova explosion, and ii) how the developing highly turbulent, neutrino-driven dynamics of the supernova influences the production of chemical elements by the explosion. These tasks will provide excellent training grounds for graduate students in theoretical nuclear physics and computational physics.The investigators and their students will use the CHIMERA neutrino radiation hydrodynamic code to perform two and three dimensional simulations of the supernova explosions for a number of star masses. In order to investigate the impact of the nuclear physics of the neutron star on the explosion, models using a series of nuclear equations of state will be explored. This study will reveal the physical regimes where the nuclear equation of state has the most influence on the supernova explosions. In order to investigate the nucleosynthesis of core-collapse supernovae, the investigators will utilize post-processing analysis (via tracer particles and a large nuclear reaction network) to explore the full nucleosynthesis impact of a range of models. This will be abetted by additional simulations that include larger, more realistic nuclear reaction networks within the CHIMERA simulations. Together, these models are expected to provide the most realistic simulation to date of the elemental and isotopic production of core-collapse supernovae.