Formation of dense gas cores in supernova remnant-cloud interactions

超新星遗迹-云相互作用中致密气体核心的形成

• 批准号: 262821815
• 负责人: Dr. Udo Ziegler
• 金额: --
• 依托单位: Leibniz-Institut für Astrophysik Potsdam (AIP)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/262821815?language=en
• 关键词: Formation; dense; gas; cores; supernova

Star formation takes place in dense, gravity-bound gas aggregations within interstellar clouds. Such pre-stellar 'cores' are believed to be created by the nonlinear interaction between gravity and strongly converging flows emerging in a turbulent environment sustained by energy input from e.g. supernova explosions. In this project, the idealized but fundamental problem is studied whether the collision of an isolated supernova remnant with an interstellar cloud is able to trigger in-situ core formation. In order to achieve this goal, high-level numerical modeling based on state-of-the-art numerics, adaptive mesh refinement and parallel computing is conducted using the NIRVANA simulation software. Our model couples magnetohydrodynamics with self-gravity, radiative cooling of the interstellar medium and anisotropic thermal conduction. Although lacking other physics like non-ideal magnetohydrodynamical processes and detailed ionisation/chemistry, the approach means a substantial improvement over current shock-cloud interaction models. Major progress in this respect stems from the development of a parallel Poisson solver and from the implementation of an efficient stiff integrator for the anisotropic thermal conduction term. The stiff integrator for conduction makes a modeling of the supernova remnant expansion computationally accessible and, hence, allows to go beyond the usually adopted small-cloud approximation.By exploring the complex interplay between all aforesaid physical effects in three-dimensional simulations the project aims to contribute to the key question under which conditions dense gas cores may be formed before the crushed cloud is disrupted by the action of magnetohydrodynamical instabilities.

恒星的形成发生在星际云中密集的、受重力约束的气体聚集中。这种恒星前的“核心”被认为是由引力和强烈汇聚流之间的非线性相互作用产生的，这些流出现在湍流环境中，由超新星爆炸等能量输入维持。在这个项目中，理想化但基本的问题是研究一个孤立的超新星遗迹与星际云的碰撞是否能够触发原位核心的形成。为了实现这一目标，利用NIRVANA仿真软件进行了基于最先进的数值模拟、自适应网格细化和并行计算的高级数值模拟。我们的模型将磁流体力学与自重力、星际介质的辐射冷却和各向异性热传导耦合在一起。尽管缺乏其他物理过程，如非理想磁流体动力学过程和详细的电离/化学，但该方法意味着对当前激波云相互作用模型的实质性改进。这方面的主要进展源于平行泊松求解器的发展和各向异性热传导项的有效刚性积分器的实现。传导的硬积分器使超新星遗迹膨胀的计算建模易于实现，因此，允许超越通常采用的小云近似。通过在三维模拟中探索上述所有物理效应之间的复杂相互作用，该项目旨在帮助解决一个关键问题，即在被粉碎的云被磁流体动力学不稳定性破坏之前，在什么条件下可能形成致密的气芯。