论文标题
双层合并期间动态增生中氦封膜点火的一维数值研究
One-Dimensional Numerical Study on Ignition of the Helium Envelope in Dynamical Accretion during the Double-Degenerate Merger
论文作者
论文摘要
为了使双次化模型对于正常的IA型超新星可行，必须避免燃烧氦气对早期可观察物的不利影响，这要求氦封膜质量最多应为0.02太阳能质量。以前的大多数研究都引起了人造热点的爆炸，因此自发性氦爆炸的稳健性仍然不确定。在目前的工作中，我们通过采用理想的一维模型和简化的7同位素反应网络，对双层通道的自发点火进行了自发的流体动力研究。我们探索了广泛的祖细胞条件，并证明直接引爆的机会有限。特别是，自发的爆炸需要> 〜0.03太阳能的主要包膜质量。相反，点火的可能性更大，这对于低至〜0.01太阳能质量而言是可行的，这可能会导致随后的爆炸爆炸过渡到爆炸过渡（DDT）。需要高分辨率的多维模拟来进一步研究DDT的可能性，并准确地得出自发爆炸与幻影点火模式之间的阈值。另一个有趣的发现是构图的效果。正如先前建议的那样，与核心材料混合会增强爆炸，但由于较低温度下的12c（Alpha，Gamma）16o反应的速度较慢，因此降低了脱脂的机会，而我们目前忽略了质子催化的12c（P，Gamma）13O（P，Gamma）13O（Alpha，ppha，p）16o的注意事项。
In order for a double-detonation model to be viable for normal type Ia supernovae, the adverse impact of helium-burning ash on early-time observables has to be avoided, which requires that the helium envelope mass should be at most 0.02 solar mass. Most of the previous studies introduced detonation by artificial hot spots, and therefore the robustness of the spontaneous helium detonation remains uncertain. In the present work, we conduct a self-consistent hydrodynamic study on the spontaneous ignition of the helium envelope in the context of the double-degenerate channel, by applying an idealized one-dimensional model and a simplified 7 isotope reaction network. We explore a wide range of the progenitor conditions, and demonstrate that the chance of direct initiation of detonation is limited. Especially, the spontaneous detonation requires the primary envelope mass of >~ 0.03 solar mass. Ignition as deflagration is instead far more likely, which is feasible for the lower envelope mass down to ~ 0.01 solar mass, which might lead to subsequent detonation once the deflagration to detonation transition (DDT) would be realized. High-resolution multi-dimensional simulations are required to further investigate the DDT possibility, as well as accurately derive the threshold between the spontaneous detonation and deflagration ignition regimes. Another interesting finding is the effect of the composition; while mixing with the core material enhances detonation as previously suggested, it rather narrows the chance for deflagration due to the slower rate of 12C(alpha,gamma)16O reaction at the lower temperature ~108K, with the caveat that we presently neglect the proton-catalyzed reaction sequence of 12C(p,gamma)13O(alpha,p)16O.
