Nucleosynthesis in tidally disrupted white dwarfs

两类黑洞是毫无疑问地建立起来的：潜伏在星系中心的超大质量黑洞和通过与X射线双星系统中正常恒星的相互作用可以检测到的恒星质量黑洞。越来越多的证据表明，第三类所谓的中等质量黑洞（IMBHs）可能存在于某些球状星团中。当恒星在星团中漂移时，有些恒星将不可避免地离黑洞足够近，从而遭受潮汐破坏。IMBH不仅有可能破坏太阳型恒星，也有可能破坏紧凑的白色矮星，这些矮星将被更大质量的黑洞作为一个整体吞噬。我们最近开始研究白色矮星的命运，这些矮星靠近黑洞足够近，以至于被破坏和压缩到某种程度，在某些情况下引发爆炸性的核燃烧。我们发现，热核点火是白色矮星的一个自然结果，只要它们穿透足够深的潮汐半径。我们的模拟使用了一个最小的核反应网络耦合到流体动力学。它被定制为准确地再现对气流的正确能量反馈，但它不能提供详细的同位素丰度。计算这种潮汐扰动的详细丰度及其与集群的混合是本提案的重点。

Two classes of black holes are established beyond reasonable doubt: supermassive black holes that lurk in centres of galaxies and stellar-mass black holes that are detectable via their interaction with normal stars in X-ray binary systems. Suggestive evidence has accumulated that a third class of so-called intermediate mass black holes (IMBHs) may exist in some globular clusters. As stars drift through the cluster, some will inevitably wander sufficiently close to the hole that they suffer a tidal disruption. IMBHs have the potential to disrupt not only solar-type stars but also compact white dwarf stars which would be swallowed as a whole by more massive black holes. We have recently begun to investigate the fate of white dwarfs that approach the hole close enough to be disrupted and compressed to such an extent that explosive nuclear burning is triggered in some cases. We found that thermonuclear ignition is a natural outcome for white dwarfs provided that they penetrate deeply enough into the tidal radius. Our simulations used a minimal nuclear reaction network coupled to the hydrodynamics. It is tailored to accurately reproduce the correct energetic feedback onto the gas flow, but it cannot deliver detailed isotopic abundances. The calculation of the detailed abundances for such tidal disruptions and their mixing with the cluster are the focus of this proposal.