Effect of Internal Structure on the Formation of Binary Near-Earth Asteroids

本课题研究的是双星近地小行星（NEAs）的内部结构对其起源和演化的影响。以前nsf支持的工作已经表明，潮汐破坏本身并不能解释二元NEAs的高人口比例。然而，YORP热效应也可以解释临界旋转、菱形和凸起的赤道脊。YORP还可以解释小型内主带小行星双星的来源，它们没有经历过潮汐破坏。考虑到弱内聚力如何影响破坏结果的初步结果，新的工作包括：1)对粒径分布、颗粒形状和模拟分辨率对潮汐和yorp式旋转破坏的影响进行系统研究；2)开发和部署弱内聚模型；3)维护和传播双小行星特性数据库。该团队独特的高性能模拟工具已经在双星NEA形成的研究中取得了重要进展，这项研究将建立在双星小行星来源上的碎石结构、弱凝聚力和接触二元性的相对重要性。鉴于快速改进的观测和最近和即将到来的航天器任务的新数据，这项理论研究是我们理解太阳系中小天体的性质和演化的重要组成部分。这项研究的结果与国家环境评估的内部结构有关，对样本返回任务和减灾战略都有影响。这项工作将是研究生论文的主要内容，将涉及本科生，并将更新观测到的二进制小天体的公共存储库。这项研究还将加强马里兰大学和法国尼斯的蓝色天文台Côte之间的国际联系。

This project is a study of the effect of internal structure on the origin and evolution of binary near-Earth asteroids (NEAs). Previous NSF-supported work has shown that tidal disruption alone cannot account for the high population fraction of binary NEAs. However, the YORP thermal effect can, and also explains the critical rotation, diamond shape, and raised equatorial ridge of the best-studied binary NEA. YORP can also explain the provenance of small inner Main Belt asteroid binaries, which have not experienced tidal disruptions. Bearing in mind preliminary results on how weak cohesion affects disruption outcome, the new work includes 1) a systematic study of the effect of particle size distribution, particle shape, and simulation resolution on tidal and YORP-style rotational disruption; 2) development and deployment of a weak cohesion model; and 3) maintenance and dissemination of a database of binary asteroid properties. The team's unique high-performance simulation tools have already been responsible for important advances in the study of binary NEA formation, and this study will establish the relative importance of rubblized structure, weak cohesion, and contact binarity, on the provenance of binary asteroids. In light of rapidly improving observations and new data from recent and forthcoming spacecraft missions, this theoretical research is an important part of our understanding of the nature and evolution of small bodies in the solar system.Results from this research bear on the internal structure of NEAs, with implications both for sample return missions and for hazard mitigation strategies. The work will be the bulk of a graduate student thesis, will involve undergraduates, and will update a public repository of observed binary small bodies. This research will also strengthen international ties between the University of Maryland and l'Observatoire de la Côte d'Azur in Nice, France.