Kinematic Models of Non-circular Features in Saturn’s Rings

Using high-resolution movie frames and azimuthal imaging scans with radial scales as fine as a few km and longitudinal resolutions as fine as a fraction of a degree, we examine the shapes and kinematics of the B-ring outer edge and the Huygens ringlet. The former is known to be strongly influenced by its proximity to the 2:1 inner Lindblad resonance with Mimas [1,2]; the latter has been suspected of being so [1]. According to basic Lindblad theory, ring particles perturbed by such a resonance should follow streamlines that take the shape of a body-centered ellipse rotating at the mean motion of the perturbing satellite. Conjunctions between the satellite and the particles should occur at periapse for particles interior to the resonance and apoapse for particles exterior to the resonance.