海王星特洛伊小天体动力学

Orbital dynamics of Neptune Trojans

特洛伊小天体与行星同享一个轨道,并与太阳、行星在空间构成等边三角形,最早为人们所知的特洛伊小天体是位于木星轨道上并位于木星前(后)方60°的两群小天体.而海王星特洛伊小天体则是近20年来太阳系内最重要的发现之一.观测证据表明海王星特洛伊小天体的总数量和总质量远超过木星特洛伊小天体和主带小行星,是太阳系内仅次于柯伊伯带的第二大小天体集群.它们一方面具有独特的轨道特征,另一方面又联系着海王星轨道内、外的空间,自然而然地成为检验太阳系起源与演化的试金石.我们简要介绍了对海王星特洛伊小天体的观测结果、对它们的轨道动力学和起源研究的进展.

Trojan asteroids share the same orbit with a planet, comprising together with the Sun and the planet an equilateral triangle in space. On the orbit of Jupiter, two clouds of thousands of asteroids named Greek Camp and Trojan Camp, by 60 degrees ahead and behind Jupiter respectively, have been well-known since as early as 1906. Trojan asteroids of Neptune however, was found quite late in the year of 2003. Nevertheless, evidences indicate that the Neptune＇s Trojan cloud is larger at least by one order of magnitude than the Jupiter Trojan cloud and the main asteroid belt, both in total number and in total mass, making itself the second largest reservoir of small bodies in the Solar system, only after the Kuiper belt. Meanwhile, the distinct orbits of Neptune Trojans that have been already observed, and the fact that they are a kind of connection between spaces within and beyond Neptune orbit, mean that they can serve as a touchstone of theories about the origin and evolution of the Solar system. We briefly present in this review the observations, the investigations on their orbital dynamics and the research on their origin.