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arXiv 2403.08552astro-ph.EP
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年轻小行星族作为陨石的主要来源

Young asteroid families as the primary source of meteorites

M. Brož, P. Vernazza, M. Marsset, F. E. DeMeo, R. P. Binzel, D. Vokrouhlický, D. Nesvorný

AI总结:

本研究揭示约70%的陨石源自三个年轻小行星族的近期解体事件,这些事件产生大量小碎片,解释了H型和L型普通球粒陨石的主导地位。

摘要:

理解明亮流星及其陨石样本的起源是最古老的天文学相关问题之一,在更大尺度上对人类具有影响[1-3]。迄今为止,只有约6%的陨石坠落被明确关联到其来源(月球、火星和小行星(4)灶神星[4-6])。在此,我们表明约70%的陨石来源于三起近期发生的直径大于30公里的小行星解体事件,这些事件分别发生在580万年前、750万年前和不到约4000万年前。这些解体事件,包括著名的Karin族[7],发生在显著但古老的Koronis族和Massalia族中,并且是H型和L型普通球粒陨石在陨石坠落中占主导地位的起源。这些年轻小行星族在所有主带小行星中因其独特的小碎片丰度而脱颖而出。它们的尺寸-频率分布在数千万年内保持陡峭,暂时超过了最大的古老小行星族(如Flora族、Vesta族)对米级碎片的产生量。支持证据包括相关尘埃带的存在[8-10]、H型球粒陨石宇宙射线暴露年龄[11,12],以及陨石进入大气层前轨道的分布[13-15]。

英文摘要:

Understanding the origin of bright shooting stars and their meteorite samples is among the most ancient astronomy-related questions that at larger scales has human consequences [1-3]. As of today, only ${\sim}\,6\%$ of meteorite falls have been firmly linked to their sources (Moon, Mars, and asteroid (4) Vesta [4-6]). Here, we show that ${\sim}\,70\%$ of meteorites originate from three recent breakups of $D > 30\,{\rm km}$ asteroids that occurred 5.8, 7.5 and less than ${\sim}\,40$ million years ago. These breakups, 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 distinguish themselves amidst all main belt asteroids by having a uniquely high abundance of small fragments. Their size-frequency distribution remains steep for a few tens of millions of years, exceeding temporarily the production of metre-sized fragments by the largest old asteroid families (e.g., Flora, Vesta). Supporting evidence includes the existence of associated dust bands [8-10], the cosmic-ray exposure ages of H-chondrite meteorites [11,12], or the distribution of pre-atmospheric orbits of meteorites [13-15].

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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