Local N-Body Simulations for the Distribution and Evolution of Particle Velocities in Planetary Rings
Local N-Body Simulations for the Distribution and Evolution of Particle Velocities in Planetary Rings
复制标题
行星环中粒子速度分布和演化的局部 N 体模拟
DOI：
10.1086/301182
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
H. Emori
中科院分区：
文献类型：
--
作者：
K. Ohtsuki;H. Emori
通过具有周期性边界条件的局部 N 体模拟，研究了一尺寸和两尺寸组件的行星环中粒子速度的分布和演化，其中包括粒子之间的碰撞和重力相互作用。三体轨道计算的数值结果可以很好地预测低光学深度系统的均方根偏心率和倾角的演变。通过Kolmogorov-Smirnov检验来检验粒子速度分布，发现当粒子的恢复系数足够小（≲0.6）以达到平衡状态时，低光学深度圆盘中粒子的轨道偏心率和倾角分布可以很好地近似为瑞利分布，而在速度色散单调增加的弹性较大的情况下，会发现高速粒子过量。然而，当光学深度较大且粒子盘在重力作用下变得不稳定时，集体尾流的影响就变得很重要。基于三体轨道计算的理论结果无法预测这种情况下的演化，偏心率和倾角偏离瑞利分布。
Distribution and evolution of particle velocities in planetary rings of one- and two-size components are investigated by a local N-body simulation with periodic boundary conditions, which includes collisions and gravitational interactions between particles. Evolution of rms eccentricities and inclinations for a system of low optical depth is found to be well predicted by the numerical results of three-body orbit calculations. The Kolmogorov-Smirnov test is performed to examine the particle velocity distribution, and it is found that the distribution of orbital eccentricities and inclinations of particles in a disk with low optical depth can be well approximated by a Rayleigh distribution when the restitution coefficient of particles is small enough (≲0.6) to achieve an equilibrium state, whereas excess of high-velocity particles is found in more elastic cases in which velocity dispersion increases monotonically. When the optical depth is larger and the disk of particles becomes gravitationally unstable, however, effects of collective wakes become important. Theoretical results based on three-body orbit calculations fail to predict the evolution in this case, and eccentricities and inclinations deviate from the Rayleigh distribution.