Tidal disruptions of white dwarfs as probes for intermediate mass black holes in globular clusters

白矮星的潮汐扰动作为球状星团中中等质量黑洞的探测器

• 批准号: 67273889
• 负责人: Professor Dr. Stephan Rosswog
• 金额: --
• 依托单位: Institutionen för astronomi
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/67273889?language=en
• 关键词: Tidal; disruptions; white; dwarfs; probes

Suggestive evidence has accumulated that intermediate mass black holes (IMBHs) exist in some globular clusters. As stars diffuse in the cluster, some will inevitably wander sufficiently close to the hole that they suffer a tidal disruption. An attractive feature of the IMBH hypothesis is its potential to disrupt not only solar-type stars but also compact white dwarf stars. We have recently investigated 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. We found that thermonuclear ignition is a natural outcome for white dwarfs of all masses passing well within the tidal radius. A peculiar, underluminous thermonuclear explosion accompanied by a soft X-ray transient signal would, if detected, be a compelling testimony for the presence of an IMBH.These previous calculations were based on the use of a relativistic pseudo-potential. In this proposal we suggest to explore the disruption process in a relativistic approach on a fixed black hole background metric. The specific goal is to implement relativistic gravity and hydrodynamics into the current hydrodynamics plus nuclear network model. Using this tool we will study particularly close encounters where strong gravity effects are important, both with rotating and non-rotating black holes.

有证据表明，在一些球状星团中存在中等质量黑洞（IMBHs）。随着恒星在星团中扩散，一些恒星将不可避免地在离黑洞足够近的地方游荡，从而遭受潮汐破坏。IMBH假说的一个吸引人的特点是，它不仅有可能破坏太阳型恒星，还可能破坏致密的白矮星。我们最近研究了白矮星的命运，这些白矮星接近黑洞的距离足够近，以至于被破坏和压缩到足以引发爆炸性核燃烧的程度。我们发现，热核着火是所有质量的白矮星经过潮汐半径范围内的自然结果。如果探测到伴随软x射线瞬态信号的特殊的暗光热核爆炸，将成为黑洞存在的有力证据。这些先前的计算是基于使用相对论伪势。在这个提议中，我们建议用相对论的方法在一个固定的黑洞背景度量上探索破坏过程。具体目标是将相对论重力和流体力学应用到当前的流体力学加核网络模型中。使用这个工具，我们将研究特别近距离的接触，在那里强引力效应很重要，无论是旋转的还是非旋转的黑洞。