日本海洋地球科学技术厅的Mikito Furuichi课题组与日本东北大学的 Hidekazu Tanaka、日本国家天文台的Eiichiro Kokubo合作，取得了一项新突破。他们研究了由粘性无摩擦球组成的多孔尘埃集聚体在碰撞过程中生长的阈值速度，并于2023年2月1日在国际学术期刊《天文学与天体物理学》上发表了相关研究成果。

该研究团队证明了颗粒间切向摩擦对尘埃集聚体碰撞生长的影响，并对由粘性和无摩擦球组成的均质多孔集聚体之间的碰撞进行了数值模拟。研究团队系统地改变了碰撞速度和碰撞角度，并计算了碰撞生长效率与碰撞速度的关系。研究人员发现，相较于具有摩擦性的球，由无摩擦球构成的尘埃集聚体在碰撞过程中生长的阈值速度降低。该研究结果凸显了切向相互作用对尘埃集聚体碰撞行为的重要性，并指出需要重建阈值速度的预测方程。

据介绍，了解尘埃聚集体的碰撞结果及其与组成颗粒的物质性质的依赖关系对于理解行星的形成具有重要意义。最近的数值模拟表明，颗粒间切向摩擦在多孔尘埃集聚体碰撞过程能量耗散中起着至关重要的作用，但切向摩擦对尘埃集聚体碰撞生长的重要性仍然知之甚少。

附：英文原文

Title: Threshold velocity for the collisional growth of porous dust aggregates consisting of cohesive frictionless spheres

Author: Sota Arakawa, Hidekazu Tanaka, Eiichiro Kokubo, Daisuke Nishiura, Mikito Furuichi

Issue&Volume: 2023/02/01

Abstract: Understanding the collisional outcomes of dust aggregates and their dependence on the material properties of the constituting particles is of great importance for understanding planet formation. Recent numerical simulations have revealed that interparticle tangential friction plays a crucial role in energy dissipation during collisions between porous dust aggregates, but the importance of friction for the collisional growth of dust aggregates remains poorly understood. Here we demonstrate the effects of interparticle tangential friction on the collisional growth of dust aggregates. We performed numerical simulations of collisions between equal-mass porous dust aggregates consisting of cohesive and frictionless spheres. We changed the collision velocity and impact angle systematically and calculated the collisional growth efficiency as a function of the collision velocity. We found that the threshold velocity for collisional growth decreases when dust aggregates are made of frictionless spheres compared to frictional spheres. Our results highlight the importance of tangential interactions for the collisional behavior of dust aggregates and indicate that the predictive equation for the threshold velocity should be reconstructed.

DOI: 10.1051/0004-6361/202345887

Source: https://www.aanda.org/articles/aa/full_html/2023/02/aa45887-23/aa45887-23.html