Orbital evolution of Saturn’s satellites due to the interaction between the moons and the massive rings
Orbital evolution of Saturn’s satellites due to the interaction between the moons and the massive rings
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DOI：
10.1051/0004-6361/202038743
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发表时间：
2020-07
影响因子：
6.5
通讯作者：
A. Nakajima;S. Ida;Yota Ishigaki
中科院分区：
文献类型：
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作者：
A. Nakajima;S. Ida;Yota Ishigaki
上下文。土星的中等大小的卫星（卫星）有一个令人费解的轨道结构，与其他卫星（土卫二和土卫二）的平均运动共振（Mimas-Tethys 4:2和土卫二2:1）。为了在一个假设的古代大质量环卫星形成的最新模型的基础上重现它们当前的轨道结构，相邻的对必须通过一阶平均运动共振而不被捕获。目标。捕获可以通过快速轨道迁移和/或卫星与环（盘）之间的引力相互作用引起的卫星偏心激发来避免，这仍然是未知的。在我们的研究中，我们通过全n体模拟来研究由于与圆盘相互作用而导致的卫星轨道演化。方法。我们进行了一个自引力粒子盘与单个卫星相互作用的全球高分辨率n体模拟。我们使用N ~ 105粒子作为磁盘。所有粒子的引力和它们的非弹性碰撞都被考虑在内。结果。稠密的短波长尾迹结构是由圆盘的自重力产生的，卫星诱导了几个全局旋臂。自重力尾迹调节卫星的轨道演化，被认为是一种圆盘扩散机制，而不是轨道演化的驱动机制。结论。卫星的自重力尾迹力矩非常有效，使得卫星的移动速度比用螺旋臂力矩预测的要快得多。它提供了一个可能的模型来避免相邻卫星对的共振捕获，并建立土星中型卫星的当前轨道配置。
Context. Saturn’s mid-sized moons (satellites) have a puzzling orbital configuration with trapping in mean-motion resonances with every-other pairs (Mimas-Tethys 4:2 and Enceladus-Dione 2:1). To reproduce their current orbital configuration on the basis of a recent model of satellite formation from a hypothetical ancient massive ring, adjacent pairs must pass first-order mean-motion resonances without being trapped. Aims. The trapping could be avoided by fast orbital migration and/or excitation of the satellite’s eccentricity caused by gravitational interactions between the satellites and the rings (the disk), which are still unknown. In our research we investigate the satellite orbital evolution due to interactions with the disk through full N-body simulations. Methods. We performed global high-resolution N-body simulations of a self-gravitating particle disk interacting with a single satellite. We used N ∼ 105 particles for the disk. Gravitational forces of all the particles and their inelastic collisions are taken into account. Results. Dense short-wavelength wake structure is created by the disk self-gravity and a few global spiral arms are induced by the satellite. The self-gravity wakes regulate the orbital evolution of the satellite, which has been considered as a disk spreading mechanism, but not as a driver for the orbital evolution. Conclusions. The self-gravity wake torque to the satellite is so effective that the satellite migration is much faster than was predicted with the spiral arm torque. It provides a possible model to avoid the resonance capture of adjacent satellite pairs and establish the current orbital configuration of Saturn’s mid-sized satellites.