In early 2019, the OSIRIS‐REx spacecraft discovered small particles being ejected from the surface of the near‐Earth asteroid Bennu.sww Although they were seen to be ejected at slow speeds, on the order of tens of cm/s, a number of particles were surprisingly seen to orbit for multiple revolutions and days, which requires a dynamical mechanism to quickly and substantially modify the orbit to prevent re‐impact upon their first periapse passage. This paper demonstrates that, based on simulations constrained by the conditions of the observed events, the combined effects of gravity, solar radiation pressure, and thermal radiation pressure from Bennu can produce many sustained orbits for ejected particles. Furthermore, the simulated populations exhibit two interesting phenomena that could play an important role in the geophysical evolution of bodies such as Bennu. First, small particles (<1 cm radius) are preferentially removed from the system, which could lead to a deficit of such particles on the surface. Second, re‐impacting particles preferentially land near or on the equatorial bulge of Bennu. Over time, this can lead to crater in‐filling and growth of the equatorial radius without requiring landslides.

中文翻译：

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从小行星本努射出的模拟粒子的动力学演化

在2019年初，OSIRIS‐REx航天器发现小颗粒从近地小行星Bennu.sww的表面喷出，尽管发现它们以慢速喷出，但速度约为几十厘米/秒，令人惊讶的是，粒子被观察到绕着轨道旋转了数圈和数天，这需要一种动力学机制来快速，实质性地改变轨道，以防止第一次撞击后再次撞击。本文证明，在受观测事件条件约束的模拟的基础上，来自Bennu的重力，太阳辐射压力和热辐射压力的综合影响可以为喷射粒子产生许多持续的轨道。此外，模拟种群显示出两个有趣的现象，它们可能在像Bennu这样的物体的地球物理演化中发挥重要作用。首先，优先从系统中除去小颗粒（半径小于1厘米），这可能会导致表面上此类颗粒不足。其次，重新撞击的粒子优先落在本努的赤道凸起附近或之上。随着时间的流逝，这可能会导致火山口填满并增加赤道半径，而无需发生滑坡。