The Fall and Origins of the Meteoroid Tanxi 后印本

摘要: Integrating available instrumental records with meteorite analysis could build a link between meteorite chemical groups and their original parent bodies. However,such comprehensive source region-tracing studies have not been conducted for any meteorite fall events in China. On 2022 December 15 at 09:48 UT,meteoroid Tanxi was recorded by numerous cameras in populous northern Zhejiang. This event offers an opportunity to conduct the first systematic origin-tracing study for a meteorite fall event in China. The Tanxi meteorite was classified as an H6 chondrite. This meteoroid entered the atmosphere with a velocity of 13.49 km s−1 and a slope of 69.52°. It most likely underwent a two-stage fragmentation process, with early fragmentation under a dynamic pressure of 0.08 MPa, and main fragmentation under a dynamic pressure of 7.83 MPa. Before colliding with the Earth, the meteoroid's heliocentric orbit had a semimajor axis of 2.363 ± 0.107 au, an eccentricity of 0.584 ± 0.019 and an inclination of 2.078 ± 0.074°. A backward Dsh evolution result of 5000 yr shows Tanxi's orbit is most similar to a small near-Earth asteroid 2016 WV2. The source region analysis of the Tanxi fall indicates that the H chondrites could originate from two distinct reservoirs: the 3:1J mean motion resonance complex (51.2 ± 3.7%) and the v6 secular resonance region (41.6 ± 2.9%).