近日，捷克共和国查尔斯大学的M. Broz及其研究团队取得一项新进展。经过不懈努力，他们发现年轻的小行星家族是陨石的主要来源。相关研究成果已于2024年10月16日在国际权威学术期刊《自然》上发表。

本研究表明，约70%的陨石源自三次近期发生的小行星解体事件，这些小行星的直径均大于30公里，解体时间分别发生在580万年前、760万年前以及不到4000万年前。这些解体事件，包括著名的卡琳族小行星解体，均发生在著名的古老柯洛尼斯族和马萨利亚族小行星中，是陨石坠落中H型和L型普通球粒陨石占主导地位的原因。

这些年轻的小行星族在主带小行星中尤为独特，因其小碎片含量异常丰富。在数千万年间，它们的尺寸-频率分布保持陡峭，一度超过了最大古老小行星族（如弗洛拉族和灶神星族）所产生的米级碎片。支持这一论点的证据包括相关尘埃带的存在、H型球粒陨石的宇宙射线暴露年龄以及陨石进入大气层前轨道的分布。

据悉，了解明亮流星及其陨石样本的起源，是与天文学相关的最古老问题之一，这一问题在更大范围内对人类具有重要影响。迄今为止，仅有约6%的陨石坠落已被明确与其来源（月球、火星或小行星灶神星）相联系。

附：英文原文

Title: Young asteroid families as the primary source of meteorites

Author: Broz, M., Vernazza, P., Marsset, M., DeMeo, F. E., Binzel, R. P., Vokrouhlick, D., Nesvorn, D.

Issue&Volume: 2024-10-16

Abstract: Understanding the origin of bright shooting stars and their meteorite samples is among the most ancient of astronomy-related questions, which at larger scales has human consequences. As of today, only approximately 6% of meteorite falls have been firmly linked to their sources (Moon, Mars or asteroid (4) Vesta). Here we show that approximately 70% of meteorites originate from three recent break-ups of D>30km asteroids that occurred 5.8, 7.6 and less than about 40Myr ago. These break-ups, including the well-known Karin family, took place in the prominent yet old Koronis and Massalia families and are at the origin of the dominance of H and L ordinary chondrites among meteorite falls. These young families are distinguished among all main belt asteroids by having a uniquely high abundance of small fragments. Their size–frequency distribution remained steep for a few tens of millions of years, exceeding temporarily the production of metre-sized fragments by the largest old asteroid families (for example, Flora and Vesta). Supporting evidence includes the existence of associated dust bands, the cosmic-ray exposure ages of H-chondrite meteorites and the distribution of the pre-atmospheric orbits of meteorites.

DOI: 10.1038/s41586-024-08006-7

Source: https://www.nature.com/articles/s41586-024-08006-7