Young asteroid families as the primary source of meteorites

• 成果类型: Article
• 署名作者: Broz, M.; Vernazza, P.; Marsset, M.; DeMeo, F. E.; Binzel, R. P.; Vokrouhlicky, D.; Nesvorny, D.
• 署名单位: Charles University Prague; Aix-Marseille Universite; Centre National de la Recherche Scientifique (CNRS); Massachusetts Institute of Technology (MIT); Southwest Research Institute
• 刊物名称: Nature
• ISSN/ISSBN: 0028-4674
• DOI: 10.1038/s41586-024-08006-7
• 发表日期: 2024-10-17
• 关键词: main-belt; collisional history; dust bands; earth; distributions; chronology; fragments; origin

摘要

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(1-3). As of today, only approximately 6% of meteorite falls have been firmly linked to their sources (Moon, Mars or asteroid (4) Vesta(4-6)). Here we show that approximately 70% of meteorites originate from three recent break-ups of D > 30 km asteroids that occurred 5.8, 7.6 and less than about 40 Myr ago. These break-ups, including the well-known Karin family(7), 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(8-10), the cosmic-ray exposure ages of H-chondrite meteorites(11,12) and the distribution of the pre-atmospheric orbits of meteorites(13-15).