Rotational Dynamics of Europa

摘要: The rotational state of Europa is only rather poorly constrained at present. It known to rotate about an axis that nearly perpendicular the orbit plane, a rate constant and approximates mean orbital rate. Small departures from rotation oscillations both lead stresses may influence location orientation surface tectonic features. However, present geological evidence for either these processes disputed. We describe variety issues future geodetic observations will likely resolve, including variations in direction rotation, on wide range timescales. Since external perturbations causing changes are generally well known, amplitude phase responses provide important information internal structure Europa. focus three aspects dynamics: obliquity, forced librations, possible small synchronous Europa’s obliquity should be nonzero, while unless lateral shell thickness occur. consequences nonzero true polar wander have yet thoroughly investigated.