JWST sighting of decametre main-belt asteroids and view on meteorite sources

• 成果类型: Article
• 署名作者: Burdanov, Artem Y.; de Wit, Julien; Broz, Miroslav; Mueller, Thomas G.; Hoffmann, Tobias; Ferrais, Marin; Micheli, Marco; Jehin, Emmanuel; Parrott, Daniel; Hasler, Samantha N.; Binzel, Richard P.; Ducrot, Elsa; Kreidberg, Laura; Gillon, Michael; Greene, Thomas P.; Grundy, Will M.; Kareta, Theodore; Lagage, Pierre-Olivier; Moskovitz, Nicholas; Thirouin, Audrey; Thomas, Cristina A.; Zieba, Sebastian
• 署名单位: Massachusetts Institute of Technology (MIT); Charles University Prague; Max Planck Society; Carl von Ossietzky Universitat Oldenburg; State University System of Florida; University of Central Florida; University of Liege; Universite Paris Saclay; CEA; Centre National de la Recherche Scientifique (CNRS); Universite Paris Cite; Max Planck Society; University of Liege; National Aeronautics & Space Administration (NASA); NASA Ames Research Center; Northern Arizona University; Leiden University - Excl LUMC; Leiden University
• 刊物名称: Nature
• ISSN/ISSBN: 0028-1643
• DOI: 10.1038/s41586-024-08480-z
• 发表日期: 2025-02-01
• 页码: 74-+
• 关键词: planetary defense; size distribution; yarkovsky; MODEL; disruption; EVOLUTION; rotation; yorp

摘要

Asteroid discoveries are essential for planetary-defence efforts aiming to prevent impacts with Earth(1), including the more frequent(2) megaton explosions from decametre impactors(3, 4, 5-6). Although large asteroids (>= 100kilometres) have remained in the main belt since their formation(7), small asteroids are commonly transported to the near-Earth object (NEO) population(8,9). However, owing to the lack of direct observational constraints, their size-frequency distribution (SFD)-which informs our understanding of the NEOs and the delivery of meteorite samples to Earth-varies substantially among models(10, 11, 12, 13-14). Here we report 138 detections of some of the smallest asteroids (greater than or similar to 10metres) ever observed in the main belt, which were enabled by JWST's infrared capabilities covering the emission peaks of the asteroids(15) and synthetic tracking techniques(16, 17-18). Despite small orbital arcs, we constrain the distances and phase angles of the objects using known asteroids as proxies, allowing us to derive sizes through radiometric techniques. Their SFD shows a break at about 100metres (debiased cumulative slopes of q=-2.660.60 and -0.97 +/- 0.14 for diameters smaller and larger than roughly 100metres, respectively), suggestive of a population driven by collisional cascade. These asteroids were sampled from several asteroid families-most probably Nysa, Polana and Massalia-according to the geometry of pointings considered here. Through further long-stare infrared observations, JWST is poised to serendipitously detect thousands of decametre-scale asteroids across the sky, examining individual asteroid families(19) and the source regions of meteorites(13,14) 'in situ'.