On 2022 September 26 23:14 UT, the NASA Double Asteroid Redirection Test spacecraft successfully impacted Dimorphos, the secondary component of the binary (65803) Didymos system, demonstrating asteroid orbit deflection for the first time. A large amount of debris, consisting of a wide size–frequency distribution of particulates (from micron-sized dust to meter-sized boulders), was released, and a long-lasting tail has been observed over more than 9 months since impact. An important fraction of the ejecta mass has been ejected as individual meter-sized boulders, as have been found in images obtained by the Light Italian CubeSat for Imaging of Asteroid (LICIACube), as well as from the Hubble Space Telescope (HST). While the boulders observed by LICIACube had projected speeds of several tens of m s^–1, those seen by the HST were about 100 times slower. In this paper, we analyze the long-term orbital evolution of those slow boulders using different dynamical codes, providing constraints on the fate of such large particles, and giving insight on the possibility of observing some of those boulders that might remain in orbit at the time of the ESA/Hera mission arrival to the binary system in late 2026.

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关于 DART 撞击 Dimorphos 后弹出的缓慢巨石的命运

世界标准时间 2022 年 9 月 26 日 23:14，美国宇航局双小行星重定向测试航天器成功撞击双态 (65803) Didymos 系统的次要组成部分 Dimorphos，首次展示了小行星轨道偏转。大量碎片被释放，其中包括各种尺寸频率分布的颗粒物（从微米大小的灰尘到米大小的巨石），并且自撞击以来的 9 个多月内观察到了持久的尾部。正如意大利轻型小行星成像立方体卫星 (LICIACube) 和哈勃太空望远镜 (HST) 获得的图像中所发现的那样，喷射物质量的重要部分已以单个米大小的巨石形式喷射出来。虽然 LICIACube 观测到的巨石预计速度为数十毫秒^–1，但 HST 观测到的巨石速度大约慢 100 倍。在本文中，我们使用不同的动力学代码分析了这些缓慢巨石的长期轨道演化，为此类大粒子的命运提供了约束，并深入了解了观察一些可能留在轨道上的巨石的可能性。 ESA/Hera 任务抵达双星系统的时间为 2026 年末。