多相星际介质流体动力学模拟中的热和非热尘埃溅射
Thermal and nonthermal dust sputtering in hydrodynamical simulations of the multiphase interstellar medium
摘要：
我们使用三维流体动力学模拟研究了超新星（SN）冲击中星际尘埃通过溅射的破坏。一个新的数值框架，我们遵循溅射和尘埃动力学直接碰撞，等离子体阻力和电子感应加速器加速。不包括颗粒之间的碰撞，并且假设粒度分布是固定的。每个SN销毁的粉尘量是量化的环境密度和拟合公式的范围很广。集成的晶粒尺寸分布，非热（惯性）溅射占主导地位的热溅射典型的环境密度。我们提出的第一个模拟，明确遵循尘埃溅射在湍流多相星际介质。我们发现，尘埃破坏的时间尺度$τ$是0.35 Gyr的硅酸盐尘埃和0.44 Gyr的碳尘埃在太阳附近的条件。SN环境对$τ$有重要影响。在预先存在的气泡中发生的SNe破坏较少的灰尘，因为破坏受到冲击气体中灰尘数量的限制。这使得$τ$比基于单个SN爆炸结果的估计长约2.5倍。我们研究了尘气质量比（DGR）的演变，发现当尺度小于10 pc时，空间不均匀性为$\sim$ 14\%。它局部正相关的气体密度，但负相关的气体温度，即使在外部的气泡，由于不完全的气体混合。这导致填充暖气体的体积中的DGR比稠密云中的DGR低$\sim$ 30\%。
英文摘要：
We study the destruction of interstellar dust via sputtering in supernova (SN) shocks using three-dimensional hydrodynamical simulations. With a novel numerical framework, we follow both sputtering and dust dynamics governed by direct collisions, plasma drag and betatron acceleration. Grain-grain collisions are not included and the grain-size distribution is assumed to be fixed. The amount of dust destroyed per SN is quantified for a broad range of ambient densities and fitting formulae are provided. Integrated over the grain-size distribution, nonthermal (inertial) sputtering dominates over thermal sputtering for typical ambient densities. We present the first simulations that explicitly follow dust sputtering within a turbulent multiphase interstellar medium. We find that the dust destruction timescales $τ$ are 0.35 Gyr for silicate dust and 0.44 Gyr for carbon dust in solar neighborhood conditions. The SN environment has an important impact on $τ$. SNe that occur in preexisting bubbles destroy less dust as the destruction is limited by the amount of dust in the shocked gas. This makes $τ$ about 2.5 times longer than the estimate based on results from a single SN explosion. We investigate the evolution of the dust-to-gas mass ratio (DGR), and find that a spatial inhomogeneity of $\sim$ 14\% develops for scales below 10 pc. It locally correlates positively with gas density but negatively with gas temperature even in the exterior of the bubbles due to incomplete gas mixing. This leads to a $\sim$ 30\% lower DGR in the volume filling warm gas compared to that in the dense clouds.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
