标题： 木星特洛伊小行星的十亿年演化与不对称问题 显示英文标题

标题： Giga-Year Evolution of Jupiter Trojans and the Asymmetry Problem

摘要： 我们进行了对观测到的小行星和虚构的木星特洛伊小行星的一系列数值积分，在太阳系年龄相当的时间跨度内，考虑了四颗外行星的引力效应。从这些结果中，我们计算了每个拉格朗日点的逃逸率，并构建了相空间不同区域“持久性”时间的动力学图。L4 和 L5 中的虚构小行星没有显著差异，显示几乎相同的动力学图和逃逸率。然而，对于真实的特洛伊小行星，我们发现领先集团约23%的成员在45亿年后逃逸，而L5处这一数字增加到了28.3%。这意味着两个群体之间的不对称性随时间增加，表明在这些小行星形成/捕获时可能较小。然而，混沌扩散的差异本身不能解释目前观测到的不对称性（约40%），这必须主要归因于特洛伊小行星捕获机制的固有特性。最后，我们使用Beaugé和Roig（2001）的半解析方法计算了所有编号特洛伊小行星的新本征元素，并将其结果与Brož和Rosehnal（2011）的数值估计进行了比较。对于2011年已经编号的小行星，两种方法得到的结果非常相似，而对于那些在2011年后成为编号的小行星，则发现了显著差异。 显示英文摘要

摘要： We present a series of numerical integrations of observed and fictitious Jupiter Trojan asteroids, under the gravitational effects of the four outer planets, for time-spans comparable with the age of the Solar System. From these results we calculate the escape rate from each Lagrange point, and construct dynamical maps of "permanence" time in different regions of the phase space. Fictitious asteroids in L4 and L5 show no significant difference, showing almost identical dynamical maps and escape rates. For real Trojans, however, we found that approximately 23% o f the members of the leading swarm escaped after 4.5 Gyrs, while this number increased to 28.3% for L5. This implies that the asymmetry between the two populations increases with time, indicating that it may have been smaller at the time of formation/capture of these asteroids. Nevertheless, the difference in chaotic diffusion cannot, in itself, account for the current observed asymmetry (~40%), and must be primarily primordial and characteristic of the capture mechanism of the Trojans. Finally, we calculate new proper elements for all the numbered Trojans using the semi-analytical approach of Beaug\'e and Roig (2001), and compare the results with the numerical estimations by Bro\v{z} and Rosehnal (2011). For asteroids that were already numbered in 2011, both methods yield very similar results, while significant differences were found for those bodies that became numbered after 2011.