文章基本信息

标题：The Lingering Death of Periodic Near-Sun Comet 323P/SOHO
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作者：Man-To Hui ; David J.Tholen ; Rainer Kracht 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2022
卷号：164
期号：1
页码：1-22
DOI：10.3847/1538-3881/ac6dcb
语种：English
出版社：American Institute of Physics
摘要：We observed near-Sun comet 323P/SOHO for the first time using ground and space telescopes. In late 2020 December, the object was recovered at Subaru showing no cometary features on its way to perihelion. However, in our postperihelion observations, it developed a long narrow tail mimicking a disintegrated comet. The ejecta, composed of at least millimeter-sized dust with power-law size distribution index 3.2 ± 0.2, was impulsively produced shortly after the perihelion passage, during which ≳0.1%–10% of the nucleus mass was shed due to excessive thermal stress and rotational disruption. Two fragments of ∼20 m in radius (assuming a geometric albedo of 0.15) were seen in Hubble Space Telescope observations from early 2021 March. The nucleus, with an effective radius of 86 ± 3 m (the same albedo assumed) and an aspect ratio of ∼0.7, has a rotation period of 0.522 hr, which is the shortest for known comets in the solar system and implies cohesive strength ≳10–100 Pa in the interior. The color of the object was freakish and changed temporally in a never-before-seen manner. Using our astrometry, we found a strong nongravitational effect following a heliocentric dependency of in the transverse motion of the object. Our N-body integration reveals that 323P has a likelihood of 99.7% to collide with the Sun in the next two millennia driven by the ν6 secular resonance.