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arXiv 2406.19337astro-ph.EP
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小行星(152830) Dinkinesh的相接双星卫星

A Contact Binary Satellite of the Asteroid (152830) Dinkinesh

Harold F. Levison, Simone Marchi, Keith S. Noll, John R. Spencer, Thomas S. Statler, the Lucy mission team

AI总结:

本文基于Lucy探测器飞掠观测,发现小行星Dinkinesh具有沟槽和赤道脊等复杂地貌,并确认其拥有首个相接双星卫星Selam,据此推断其演化由YORP自旋加速导致质量破坏与物质再吸积。

摘要:

直径小于约5公里的小行星具有复杂的历史,因为它们足够小,使得辐射力矩(YORP效应)成为其演化中的一个显著因素。(152830) Dinkinesh是一颗小行星,绕太阳运行于主小行星带内缘附近,其日心半长轴为2.19天文单位;它的S型光谱是主带这一区域天体的典型特征。本文报告了Lucy航天器在距Dinkinesh 431公里范围内飞掠时所进行的观测。Lucy揭示出Dinkinesh的有效直径仅约720米,却出乎意料地复杂。尤其值得注意的是,其表面存在一条显著的纵向沟槽,其上覆盖着一条巨大的赤道脊,并且发现了首个经确认的相接双星卫星,现命名为(152830) Dinkinesh I Selam。Selam由两个大小几乎相等的瓣组成,直径分别约为210米和230米。它以约52.7小时的轨道周期在距Dinkinesh 3.1公里处绕行,并且处于潮汐锁定状态。该系统的动力学状态、角动量以及地貌观测使我们推断,Dinkinesh的脊和沟槽很可能是由YORP效应导致的自旋加速引发质量破坏,随后抛射物质部分重新吸积的结果。Selam很可能由该事件抛射出的物质吸积而成。

英文摘要:

Asteroids with diameters less than about 5 km have complex histories because they are small enough for radiative torques, YORP, to be a notable factor in their evolution. (152830) Dinkinesh is a small asteroid orbiting the Sun near the inner edge of the Main Asteroid Belt with a heliocentric semimajor axis of 2.19 AU; its S type spectrum is typical of bodies in this part of the Main Belt. Here we report observations by the Lucy spacecraft as it passed within 431 km of Dinkinesh. Lucy revealed Dinkinesh, which has an effective diameter of only $\sim$720 m, to be unexpectedly complex. Of particular note is the presence of a prominent longitudinal trough overlain by a substantial equatorial ridge, and the discovery of the first confirmed contact binary satellite, now named (152830) Dinkinesh I Selam. Selam consists of two near-equal sized lobes with diameters of $\sim$210 m and $\sim$230 m. It orbits Dinkinesh at a distance of 3.1 km with an orbital period of about 52.7 hr, and is tidally locked. The dynamical state, angular momentum, and geomorphologic observations of the system lead us to infer that the ridge and trough of Dinkinesh are probably the result of mass failure resulting from spin-up by YORP followed by the partial reaccretion of the shed material. Selam probably accreted from material shed by this event.

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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