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arXiv 0906.4384astro-ph.SR
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Ia型超新星系统演化的评价:前身星Ne22含量对动力学的影响

Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Progenitor Ne22 Content on Dynamics

Dean M. Townsley, Aaron P. Jackson, Alan C. Calder, David A. Chamulak, Edward F. Brown, F. X. Timmes

摘要:

我们提出了一个理论框架,在超新星Ia型(SN Ia),利用2-D模拟实施的爆燃-爆震过渡(DDT)爆炸方案的形式的系统性影响的正式研究。该框架是从一个随机的初始条件,导致一个样本的模拟超新星Ia的镍56质量有一个类似的平均值和范围观察到的,并有许多其他适度现实的功能,如速度范围的中间质量元素。其预期目的是能够对Ia超新星爆炸模拟的物理和理论参数进行统计上明确的研究。我们在这里提出了一个彻底的描述,我们目前的模拟产生的超新星爆炸的结果。这个框架的第一个应用程序是用来研究的依赖性的超新星Ia的Ne 22的内容,这是已知的直接影响的祖先恒星人口的金属丰度。我们的研究是专门针对测量Ne 22含量如何影响燃烧物质羽流的上升与恒星膨胀之间的竞争,然后这些羽流达到DDT条件。这种竞争控制了处于核统计平衡(NSE)的物质的数量,因此通过设定在爆炸的爆炸阶段发生核合成的密度来产生Ni 56。尽管任何特定点火条件下的结果都可能随着Ne 22含量的变化而发生显著变化,但通过20种点火条件的样本,我们发现爆炸前恒星膨胀的系统变化不足以与Timmes,Brown和Truran(2003)讨论的初始中子过剩的依赖性相竞争。(节录)

英文摘要:

We present a theoretical framework for formal study of systematic effects in Supernovae Type Ia (SN Ia) that utilizes 2-d simulations to implement a form of the deflagration-detonation transition (DDT) explosion scenario. The framework is developed from a randomized initial condition that leads to a sample of simulated SN Ia whose Ni56 masses have a similar average and range to those observed, and have many other modestly realistic features such as the velocity extent of intermediate mass elements. The intended purpose is to enable statistically well-defined studies of both physical and theoretical parameters of the SN Ia explosion simulation. We present here a thorough description of the outcome of the SN Ia explosions produced by our current simulations. A first application of this framework is utilized to study the dependence of the SN Ia on the Ne22 content, which is known to be directly influenced by the progenitor stellar population's metallicity. Our study is very specifically tailored to measure how the Ne22 content influences the competition between the rise of plumes of burned material and the expansion of the star before these plumes reach DDT conditions. This competition controls the amount of material in nuclear statistical equilibrium (NSE) and therefore Ni56 produced by setting the density at which nucleosynthesis takes place during the detonation phase of the explosion. Although the outcome following from any particular ignition condition can change dramatically with Ne22 content, with a sample of 20 ignition conditions we find that the systematic change in the expansion of the star prior to detonation is not large enough to compete with the dependence on initial neutron excess discussed by Timmes, Brown & Truran (2003). (Abridged)

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