小天体环的轨道动力学

随着天文观测的深入，发现不仅土星、木星等气态巨行星环绕有光环，某些小天体也环绕有光环。针对目前发现环的半人马型小天体女凯龙星（10199 Chariklo），研究其引力场中粒子（视为质点）的轨道动力学，分析赤道椭率和小天体自转对环中粒子轨道运动的影响，通过庞加莱截面中的KAM环迭代，得到第一类周期轨道和1∶3共振周期轨道，并通过对比和分析得到小天体光环位置与小天体自转平运动共振的关系。研究结果表明:女凯龙星内环中的粒子最可能处在满足径向振荡幅值范围的第一类周期轨道及其附近的准周期轨道上，但不能排除处在1∶3共振周期轨道及其附近的准周期轨道上；外环中的粒子不可能处在1∶3共振周期轨道上，只可能处在第一类周期轨道及其附近的准周期轨道上。 

Orbital dynamics of rings of small bodies

With the development of astronomical observations, it has been found that, not only Saturn, Jupiter and other giant planets, but also some small bodies are surrounded by rings. Focussing on rings of the Centaur 10199 Chariklo, we study the orbital dynamics of particles in the gravitational field of Chariklo, and analyze the impacts of equatorial ellipticity and rotation of Chariklo on the orbital motion of particles. The first kind of periodic orbits and 1:3 resonant periodic orbits are obtained by using KAM torus iteration on the Poincaré sections. The relationship between the position of rings and the mean motion resonances are revealed by analyzing the properties of the periodic orbits. The results show that, the particles in the inner ring of Chariklo are most likely associated with the first kind of periodic orbits and their quasi-periodic orbits, but are also likely associated with the 1:3 resonant periodic orbits and their quasi-periodic orbits. The particles in the outer ring of Chariklo are not associated with the 1:3 resonant periodic orbits, but are associated with the first periodic orbits and their quasi-periodic orbits.