Microphysical modeling of comets and planetesimals

彗星和星子的微物理模型

• 批准号: 51912759
• 负责人: Professor Dr. Jürgen Blum
• 金额: --
• 依托单位: Institut für Geophysik und Extraterrestrische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/51912759?language=en
• 关键词: Microphysical; modeling; comets; planetesimals

Motivated by our recent results from laboratory experiments on the formation of macroscopic highporosity dust aggregates with physical properties matching those observed in comets and by new close-up observations of cometary nuclei, this proposal intends to derive at a detailed description of the physical processes in the near-surface layers of a cometary nucleus and the transition region between nucleus and coma. In this project, we will perform so far unfeasible laboratory experiments on the gas permeability and thermal properties of cometary analogs as well as on the dynamical interactions of loosely-bound dust grains with rarefied-gas flows. These experimental results will then be used to calibrate our new thermophysical model of the cometary surface and the transition region between nucleus and coma, which will consist of an improved morphological description of the outer layers of the cometary nucleus, an improved treatment of mass and energy transfer in the nucleus and in the coma, and a model of the dust acceleration in the vicinity of the cometary surface. As a side-effect, we will also arrive at a better description of the dust-dust interaction in protoplanetary disks, which involves very similar physical properties as those present in comets. By combining the expertise of an experimental (IGEP) and a theoretical/observational (MPS) group, our model will encompass the complete picture that we currently have of the physical processes close to a cometary nucleus and of protoplanetary precursors of comets, the planetesimals/cometesimals.

我们最近在实验室实验中发现了与彗星中观测到的物理特性相匹配的宏观高孔隙度尘埃聚集体的形成，并通过对彗星核的新的近距离观测，本提案旨在对彗星核近表面层和核与彗发之间过渡区域的物理过程进行详细描述。在这个项目中，我们将对彗星类似物的透气性和热性能以及松散结合的尘埃颗粒与稀薄气流的动态相互作用进行迄今为止不可行的实验室实验。这些实验结果将被用来校准我们新的彗星表面和彗核与彗发之间过渡区域的热物理模型，该模型将包括改进的彗核外层形态学描述，改进的彗核和彗发中质量和能量传递处理，以及彗星表面附近尘埃加速的模型。作为一个副作用，我们还将更好地描述原行星盘中的尘埃相互作用，这涉及到与彗星中存在的非常相似的物理性质。通过结合实验组（IGEP）和理论/观测组（MPS）的专业知识，我们的模型将涵盖我们目前所拥有的彗星核附近的物理过程和彗星的原行星前体（星子/星子）的完整图景。