论文标题
部分可观测时空混沌系统的无模型预测
A Self-Consistent Model for Dust-Gas Coupling in Protoplanetary Disks
论文作者
论文摘要
HH/HE HE/HE，气体相互作用促进了原星盘内随后发生的各种物理过程 - 包括冰冷/岩石晶粒的垂直沉降，固体的径向漂移，行星形成以及行星积聚本身 - 由H/HE/HE气体相互作用促进。量化尘埃气耦合强度的Stokes数量，因此在原月球磁盘的演化中起着核心作用，其不良的确定构成了行星形成理论中不确定性的重要来源。在这项工作中，我们提出了一个简单的粉尘耦合模型，并证明，对于nebular积聚速率的指定组合，$ \ dot {m} $和湍流参数，$α$，可以独特地计算出Stokes数字的径向概况。我们的模型表明，Stokes数字在轨道半径上以下线生长，但在水冰线上急剧增加。对于$ \ dot {m} = 10^{ - 8} \，m _ {\ odot}/$年和$α= 10^{ - 3} $，我们的理论产生$ \ Mathrm {sT} $ {sT} $ {stokes的特征值，对于$ \ dot {m} = 10^{ - 8} \，m _ {\ odot}/$年，$ \ mathrm {st} $ { - 4.4，对于基于$ \ mathrm {st} $ {st}的特征值，对于$ \ dot {m} = 10^{ - 8} \，M _ {\ odot}/$年，$ \ dot $ \ sim $ mm大小的硅酸盐灰尘）在内部星云中，$ \ mathrm {st} \ sim10^{ - 1} $（对应于磁盘的外部区域的$ \ sim $ $ $ $ $ cm大小的冰谷）。因此，预计固体将在较大的以星形为中心的距离下沉降到薄的子盘中，同时在冰线内保持垂直固定良好。
Various physical processes that ensue within protoplanetary disks -- including vertical settling of icy/rocky grains, radial drift of solids, planetesimal formation, as well as planetary accretion itself -- are facilitated by hydrodynamic interactions between H/He gas and high-$Z$ dust. The Stokes number, which quantifies the strength of dust-gas coupling, thus plays a central role in protoplanetary disk evolution, and its poor determination constitutes an important source of uncertainty within the theory of planet formation. In this work, we present a simple model for dust-gas coupling, and demonstrate that for a specified combination of the nebular accretion rate, $\dot{M}$, and turbulence parameter, $α$, the radial profile of the Stokes number can be calculated uniquely. Our model indicates that the Stokes number grows sub-linearly with orbital radius, but increases dramatically across the water-ice line. For fiducial protoplanetary disk parameters of $\dot{M}=10^{-8}\,M_{\odot}/$year and $α=10^{-3}$, our theory yields characteristic values of the Stokes number on the order of $\mathrm{St}\sim10^{-4}$ (corresponding to $\sim$mm-sized silicate dust) in the inner nebula and $\mathrm{St}\sim10^{-1}$ (corresponding to $\sim$few-cm-sized icy grains), in the outer regions of the disk. Accordingly, solids are expected to settle into a thin sub-disk at large stellocentric distances, while remaining vertically well-mixed inside the ice line.
