主带小行星的动力学模拟

Dynamical Simulation of Asteroids in the Main Belt

采用接近真实太阳系的动力学模型，对主带小行星的动力学演化进行了数值模拟。计算的起始时间是儒略目JD=2．4540005×10^6，计算的时间长度为100万年。力学模型采用n＋m体模型，计算程序基于小行星轨道演化的软件Orbit9。对演化结果进行分析可以发现测试粒子与木星的平运动共振对测试粒子稳定性的不同作用，以及在2：3、3：4共振处不同初始ω值对测试粒子演化结果的影响。

By using a dynamical model approach of real solar system, a numerical simulation of the dynamical evolution of the main belt asteroids in solar system is made. The evolution of the test particles with a time span of 1 million years from the beginning of Julian day JD= 2.454 000 5 × 10^6 by using the Orbit9 integrator, which is designed specially to compute the orbit evolution of small bodies, is calculated. The dynamical model used in this paper is a system of n ＋ rn bodies, where n equals 7 which means the mass of Mercury and Venus are merged into the mass of Sun and the mass of Pluto is ignored, meanwhile the interaction among the Sun and the rest 6 planets is considered; the number of test particles, m, equals 25 000 in this model. The model for the initial distribution of the test particles is： there are 5 groups of test particles with different argument of pericenter （ω） which are 0°, 72°, 144°, 216° and 288°, the semi major axis （a） of each group distributes between 1.5~4.5 AU evenly with an interval of 6 ×10^-4 AU, the eccentricity （e） and orbital inclination （i） of all particles are set to be the same values of e=0.1 and i=8° as they distribute in the solar system, the longitude of Ascending Node Ω=0°, and the mean anomaly M=0. The results show the different effects of mean motion resonance between the Jupiter and the test particles on the stability of the test particles and the influence of different initial value of ω at 2 ： 3 and 3 ： 4 resonant zones on the evolution of the test particles.