论文标题
超音速星际湍流中分子的增生尘埃生长
Dust growth by accretion of molecules in supersonic interstellar turbulence
论文作者
论文摘要
我们表明，通过湍流稀释气体的高度可压缩性，冷分子云中的粉尘晶粒的生长速率增强了。通过高分辨率（10243）数值模拟，我们证实了以下理论：空间平均生长速率与气体密度方差成正比。这也导致晶粒大小分布（GSD）扩大，这是由于湍流引起的晶粒生长速率变化。我们首次在对流体动力湍流的详细数值模拟中首次显示，GSD朝着反映气体密度分布的形状演变而成，无论初始分布如何。也就是说，在等温的情况下，旋转强迫湍流，GSD往往是对数正态分布。我们还表明，在超声波湍流中，气体和粉尘的脱钩变得重要，这导致了进一步加速的谷物生长。
We show that the growth rate of dust grains in cold molecular clouds is enhanced by the high degree of compressibility of a turbulent, dilute gas. By means of high resolution (10243) numerical simulations, we confirm the theory that the spatial mean growth rate is proportional to the gas-density variance. This also results in broadening of the grain-size distribution (GSD) due to turbulence-induced variation of the grain-growth rate. We show, for the first time in a detailed numerical simulation of hydrodynamic turbulence, that the GSD evolves towards a shape which is a reflection of the gas-density distribution, regardless of the initial distribution. That is, in case of isothermal, rotationally forced turbulence, the GSD tends to be a lognormal distribution. We also show that in hypersonic turbulence, decoupling of gas and dust becomes important and that this leads to an even further accelerated grain growth.
