A Simple Parameterization of the Consequences of Deleptonization for Simulations of Stellar Core Collapse
A Simple Parameterization of the Consequences of Deleptonization for Simulations of Stellar Core Collapse
复制标题
恒星核心塌陷模拟中去轻子化后果的简单参数化
DOI：
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发表时间：
2005
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通讯作者：
M. Liebendörfer
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作者：
M. Liebendörfer
提出了一种简单而高效的去轻子化、熵变化和中微子应力的参数化方法，用于恒星核坍塌的数值模拟。中微子物理的参数是基于电子分数的反弹轮廓，因为它是由球对称的多群Boltzmann中微子输运的最先进的坍塌模拟产生的。另外两个参数包括平均中微子逃逸能量和中微子捕获密度。参数化模拟再现了崩溃阶段微妙的中微子热化-扩散过程的后果，并提供了一个比绝热近似更现实的选择，绝热近似通常用于研究引力波的发射、多维广义相对论效应、磁场的演化，甚至在模拟核坍塌和反弹时研究核合成。对于专门为反弹后阶段设计的超新星代码，参数化在恒星演化代码的适用性结束点和反弹后演化开始点之间建立了一座方便的桥梁。
A simple and computationally efficient parameterization of the deleptonization, the entropy changes, and the neutrino stress is presented for numerical simulations of stellar core collapse. The parameterization of the neutrino physics is based on a bounce profile of the electron fraction as it results from state-of-the-art collapse simulations with multigroup Boltzmann neutrino transport in spherical symmetry. Two additional parameters include an average neutrino escape energy and a neutrino trapping density. The parameterized simulations reproduce the consequences of the delicate neutrino thermalization-diffusion process during the collapse phase and provide a by far more realistic alternative to the adiabatic approximation, which has often been used in the investigation of the emission of gravitational waves, of multidimensional general relativistic effects, of the evolution of magnetic fields, or even of the nucleosynthesis in simulations of core collapse and bounce. For supernova codes that are specifically designed for the postbounce phase, the parameterization builds a convenient bridge between the point where the applicability of a stellar evolution code ends and the point where the postbounce evolution begins.