论文标题

二进制小行星二级成分上的旋转引起的颗粒运动:对飞镖的应用对Dimorphos的影响

Rotation-induced granular motion on the secondary component of binary asteroids: Application to the DART impact on Dimorphos

论文作者

Agrusa, Harrison, Ballouz, Ronald, Meyer, Alex J., Tasev, Elisa, Noiset, Guillaume, Karatekin, Özgur, Michel, Patrick, Richardson, Derek C., Hirabayashi, Masatoshi

论文摘要

NASA的双重小行星重定向测试(DART)任务将对Didymos二元小行星系统的二级成分进行动力影响,这将激发Dimorphos的动态状态,并导致有关同步状态和可能的chaotic chaotic noce chaotic nongotic and chaotic nongotic agotic nortagotic axis axis旋转。尽管这种特殊的结果是人类引起的,但二元系统的许多其他次要组成部分也容易出现这种异国情调的旋转状态。对于以激发自旋状态的卫星,随着时变的潮汐和旋转环境可以导致明显的表面加速。根据情况,这种机制可能会驱动次级表面上的颗粒状运动。我们使用完全耦合的三维仿真代码对Didymos样二进制小行星系统的动力学演变进行了建模。然后,我们计算了由于继发性动力学状态而导致的整个表面上感觉到时变的引力和旋转加速度。我们发现激发的自旋和轨道可以诱导有效的表面斜率发生巨大变化,从而可能触发颗粒状运动和表面茶点。但是,对于DART撞击的情况,这种效应高度取决于许多未知数,例如Dimorphos的详细形状,散装密度,表面地质和转移的动量。除了Didymos系统和DART任务外,这种效果对总体上对二进制系统也具有重要意义。

NASA's Double Asteroid Redirection Test (DART) mission will kinetically impact Dimorphos, the secondary component of the Didymos binary asteroid system, which will excite Dimorphos's dynamical state and lead to significant libration about the synchronous state and possibly chaotic non-principal axis rotation. Although this particular outcome is human caused, many other secondary components of binary systems are also prone to such exotic spin states. For a satellite in an excited spin state, the time-varying tidal and rotational environment can lead to significant surface accelerations. Depending on the circumstances, this mechanism may drive granular motion on the surface of the secondary. We modeled the dynamical evolution of a Didymos-like binary asteroid system using a fully coupled, three-dimensional simulation code. Then, we computed the time-varying gravitational and rotational accelerations felt over the entire surface resulting from the secondary's perturbed dynamical state. We find that an excited spin and orbit can induce large changes in the effective surface slope, potentially triggering granular motion and surface refreshment. However, for the case of the DART impact, this effect is highly dependent on many unknowns, such as Dimorphos's detailed shape, bulk density, surface geology, and the momentum transferred. Aside from the Didymos system and the DART mission, this effect also has important implications for binary systems in general.

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