The Origin and Evolution of Transneptunian Binaries: Excitation of Binary Orbit Eccentricity via the Kozai-Lidov Mechanism

This animation shows the evolution of the properties of binary planetesimals during a simulation of the outward migration of Neptune, as presented in the PhD thesis: "The Origin and Evolution of Transneptunian Binaries" by J. E. Robinson. The figure axes indicate the binary semimajor axis and eccentricity, while the colour scheme denotes the binary orbit inclination. During the simulation binaries above a critical separation (denoted by the red vertical line) undergo oscillations in eccentricity which allow them to evolve onto non-circular orbits (above the horizontal red line). These objects are experiencing binary orbit Kozai-Lidov oscillations; only binaries with inclinations sensitive to Kozai (40 < i < 140 degrees) display this behaviour.

本动画展示了J.E.罗宾逊（J. E. Robinson）的博士论文《The Origin and Evolution of Transneptunian Binaries》（《海王星外双星的起源与演化》）中所呈现的海王星向外迁移数值模拟过程中，双星星子（binary planetesimals）的属性演化情况。该可视化图像的坐标轴分别表示双星的半长轴（semimajor axis）与偏心率（eccentricity），配色方案则用于表征双星轨道倾角（inclination）。在模拟过程中，临界间距（由红色竖线标示）以上的双星会发生偏心率振荡，使其得以演化至非圆轨道（位于红色水平线之上）。这类天体正经历双星轨道的科赖伊-利多夫振荡（Kozai-Lidov oscillations）；仅当双星倾角处于科赖伊效应敏感区间（40° < i < 140°）时，才会表现出该行为。