The Inclination-Type Resonance of Mimas and Tethys

Abstract

The traditional analysis of the motion of Mimas and Tethys obscures the physical process governing their resonance. The satellites' mutual perturbations tend to draw conjunction toward longitudes 90° from the mutual nodes of their orbits. Combined with the relatively fast rate of precession of the ascending nodes on Saturn's equatorial plane due to the planet's oblateness, this effect results in the observed libration of conjunction about the average longitude of the two ascending nodes. This mechanism may help to explain the formation of the resonance.