SPONTANEOUS INITIATION OF DETONATIONS IN WHITE DWARF ENVIRONMENTS: DETERMINATION OF CRITICAL SIZES
SPONTANEOUS INITIATION OF DETONATIONS IN WHITE DWARF ENVIRONMENTS: DETERMINATION OF CRITICAL SIZES
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DOI：
10.1088/0004-637x/696/1/515
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发表时间：
2009-01
期刊：
影响因子：
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通讯作者：
I. Seitenzahl;C. Meakin;D. Townsley;D. Lamb;J. Truran
中科院分区：
文献类型：
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作者：
I. Seitenzahl;C. Meakin;D. Townsley;D. Lamb;J. Truran
一些Ia型超新星（SNe Ia）的爆炸模型，如引力约束爆轰（GCD）或双爆轰亚爆轰（DDSC）模型，依赖于白色矮星（WD）的简并/材料中的爆轰自发引发。众所周知，在多维恒星模拟中，与爆炸起始有关的长度尺度是无法解决的，这促使人们使用更高分辨率的一维模拟结果，例如为这项工作进行的模拟结果，作为指导方针，用于决定在高维全星星模拟中成功达到的条件是否会导致爆炸的发生。自发启动依赖于存在一个合适的梯度自燃（感应）时间的燃料，我们设置了一个空间局部化的温度不均匀性热点。我们确定的临界（最小）尺寸的热点，仍然轻微导致爆炸WD物质的反应欧拉方程与流体动力学代码闪光集成。我们量化了这些热点的临界尺寸对成分、背景温度、峰值温度、几何形状和温度扰动的功能形式的依赖性，其中许多是迄今为止文献中未探索的。我们讨论了我们的研究结果的背景下，SNE Ia的建模的影响。
Some explosion models for Type Ia supernovae (SNe Ia), such as the gravitationally confined detonation (GCD) or the double detonation sub-Chandrasekhar (DDSC) models, rely on the spontaneous initiation of a detonation in the degenerate / material of a white dwarf (WD). The length scales pertinent to the initiation of the detonation are notoriously unresolved in multidimensional stellar simulations, prompting the use of results of one-dimensional simulations at higher resolution, such as those performed for this work, as guidelines for deciding whether or not conditions reached in the higher dimensional full star simulations successfully would lead to the onset of a detonation. Spontaneous initiation relies on the existence of a suitable gradient in self-ignition (induction) times of the fuel, which we set up with a spatially localized nonuniformity of temperature—a hot spot. We determine the critical (smallest) sizes of such hot spots that still marginally result in a detonation in WD matter by integrating the reactive Euler equations with the hydrodynamics code flash. We quantify the dependences of the critical sizes of such hot spots on composition, background temperature, peak temperature, geometry, and functional form of the temperature disturbance, many of which were hitherto largely unexplored in the literature. We discuss the implications of our results in the context of modeling of SNe Ia.