Project P6: Collision properties of solids in debris disks at low to moderate impact velocities

项目 P6：低至中等冲击速度下碎片盘中固体的碰撞特性

• 批准号: 278211407
• 负责人: Professor Dr. Jürgen Blum
• 金额: --
• 依托单位: Osservatorio Astronomico di Padova
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/278211407?language=en
• 关键词: Project; P6; Collision; properties; solids

Debris disks form due to collisions among planetesimals in which the colliding bodies are partly fragmented. As the strength of the planetesimals and their fragments determines the size distribution, it is essential to study the collisional outcome of solids grown at the protoplanetary phase under the conditions of debris disks. Melting or sintering effects are rather unimportant for not too large planetesimals so that the colliding bodies should be aggregates of (sub-)micrometer-sized dust and ice particles, which are held together by van der Waals and dipole forces. We will investigate in the laboratory the collision physics of dust and ice aggregates formed at the protoplanetary phase under the conditions of debris disks. In particular, we will derive the onset velocity for fragmentation, the velocity at which the largest fragment equals half the mass of the colliding bodies, the size distribution of fragments as a function of impact velocity, and the mass-velocity correlation as well as the velocity-vector distribution of the fragments for dust and ice aggregates in the mm to dm size range. To achieve these goals, we will utilize existing experimental setups in the Braunschweig laboratory with which collision speeds between ~ 1 m/s and ~ 1000 m/s can be achieved. As a result, we will derive an empirical collision model for debris-disk dust and ice aggregates that will be directly usable in P1, P2, and P3. On top of that, we will also provide samples in a wide porosity range for P5 for further investigation of their optical properties.

碎片盘的形成是由于小行星之间的碰撞，其中碰撞的物体部分破碎。由于星子及其碎片的强度决定了大小分布，因此必须研究在碎片盘条件下原行星阶段生长的固体的碰撞结果。熔化或烧结效应对于不太大的微行星是相当不重要的，因此碰撞体应该是（亚）微米大小的尘埃和冰粒的聚集体，它们通过货车德瓦尔斯力和偶极力结合在一起。我们将在实验室中研究在原行星阶段碎片盘条件下形成的尘埃和冰聚集体的碰撞物理学。特别是，我们将推导出破碎的起始速度，最大的碎片等于碰撞物体质量的一半时的速度，作为碰撞速度的函数的碎片的尺寸分布，以及质量-速度相关性以及在毫米至分米尺寸范围内的尘埃和冰聚集体的碎片的速度矢量分布。为了实现这些目标，我们将利用布伦瑞克实验室中现有的实验装置，可以实现约1 m/s和约1000 m/s之间的碰撞速度。因此，我们将推导出一个经验碰撞模型的碎片盘灰尘和冰聚集体，将直接用于P1，P2和P3。除此之外，我们还将为P5提供宽孔隙率范围的样品，以进一步研究其光学特性。