真实气体动力学下的星子形成：湍流与有风原行星盘中的尘埃聚集
Planetesimal Formation under Realistic Gas Dynamics: Dust Concentration in Turbulent and Windy Protoplanetary Disks
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中文总结 AI 辅助
本研究通过Athena++模拟发现，在含环境扩散和磁风的外盘条件下，强尘埃团块持续存在，且磁风通过气体耗散和尘埃捕获增强团块，有利于星子形成。
中文摘要 AI 辅助
星子是行星形成的关键中间阶段，源于原行星盘中受气体动力学强烈调控的尘埃聚集。本研究利用Athena++的多流体尘埃模块，在二维轴对称全局非理想磁流体动力学（MHD，即磁流体动力学）模拟中，研究了外部盘中的尘埃聚集，其中考虑了环境扩散（AD，即环境扩散）。我们的模拟同时启动了大规模MHD盘风，并解析了流动不稳定性（SI，即流动不稳定性）和垂直切变不稳定性（VSI，即垂直切变不稳定性）。我们系统地探讨了磁场强度、冷却时标、环境扩散Elsasser数和尘埃尺寸对尘埃聚集的影响。我们发现，在广泛的磁化及有风盘条件下，强尘埃团块持续存在。MHD风还通过以下方式改变背景条件而增强尘埃团块：（1）MHD风质量损失导致的长期气体耗散，以及（2）磁场通量集中（在磁场更强的情况下发生）引起的纬向流中的尘埃捕获。总体而言，我们的结果表明，在具有AD和大规模MHD风的全局磁化盘中，强尘埃团块可以持续存在，从而为星子形成创造有利条件。
英文摘要
Planetesimals are a key intermediate stage of planet formation and originate from dust concentration in protoplanetary disks, which is strongly regulated by gas dynamics. In this study, we use the multifluid dust module of Athena++ to investigate dust concentration in 2D axisymmetric global non-ideal MHD (ambipolar diffusion, AD) simulations of outer disks. Our simulations simultaneously launch large-scale MHD disk winds and resolve both streaming instability (SI) and vertical shear instability (VSI). We systematically explore the effects of magnetic field strength, cooling timescale, ambipolar Elsasser number, and dust size on dust concentration. We find that strong dust clumping persists across a broad range of magnetized and wind-launching disk conditions. MHD winds also enhance dust clumping by modifying background conditions in the following ways: (1) secular gas depletion by MHD wind mass loss, and (2) dust trapping in zonal flows as a result of magnetic flux concentration (which occurs in more strongly magnetized cases). Overall, our results demonstrate that strong dust clumping can persist in global magnetized disks with AD and large-scale MHD winds, leading to conditions favorable for planetesimal formation.
发表机构
- CAS Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院行星科学重点实验室、紫金山天文台）
- Institute for Advanced Study, Tsinghua University（清华大学高等研究院）
- Department of Astronomy, Tsinghua University（清华大学天文学系）
机构由 AI 辅助整理，请以论文原文为准。
