Charon: A brief history of tides

Tidal evolution of the Pluto-Charon binary

A giant collision is believed to be at the origin of the Pluto-Charon system. As a result, the initial orbit and spins after impact may have substantially differed from those observed today. More precisely, the distance at periapse may have been shorter, subsequently expanding to its current separation by tides raised simultaneously on the two bodies. Here we provide a general 3D model to study the tidal evolution of a binary composed of two triaxial bodies orbiting a central star. We apply this model to the Pluto-Charon binary, and notice some interesting constraints on the initial system. We…

行星被其卫星潮汐同步的初始条件

Initial conditions for tidal synchronisation of a planet by its moon

本文基于角动量守恒推导了行星被卫星潮汐同步的通用初始条件，该条件与行星内部结构无关，适用于收缩和扩张轨道及逆行运动，并通过太阳系实例和系外行星应用展示了其约束演化场景的能力。

Tidal Constraints on Planetary Habitability

We review how tides may impact the habitability of terrestrial-like planets. If such planets form around low-mass stars, then planets in the circumstellar habitable zone will be close enough to their host stars to experience strong tidal forces. We discuss 1) decay of semi-major axis, 2) circularization of eccentric orbits, 3) evolution toward zero obliquity, 4) fixed rotation rates (not necessarily synchronous), and 5) internal heating. We briefly describe these effects using the example of a 0.25 solar mass star with a 10 Earth-mass companion. We suggest that the concept of a habitable zone …

主序星系外行星系统：潮汐演化

Main-sequence exoplanet systems: tidal evolution

本研究聚焦近宿主恒星的系外行星，介绍潮汐物理学基础，阐述潮汐对这类行星轨道、半径及演化的作用，以及潮汐在已观测系外行星种群中留下的特征印记。