A simulated image of Saturn’s rings from the “granola bar” self-gravity wake model.
Self-gravity wakes are ephemeral elongated aggregates of ring particles which are canted from the direction of orbital motion by about 25º due to Keplerian shear (see insert). When Saturn’s rings are observed from far away, individual self-gravity wakes, which have a length scale of ~100m cannot be seen, however they cause azimuthal asymmetry in brightness and transparency. In this image, the rings are most transparent at the 2 o’clock and 8 o’clock positions with the observer at 6 o’clock. Transparency is shown in a scale from black (most transparent), to green, to red, to white (most opaque). The transparencies of the rings in this image were derived from self-gravity wake heights, widths, separations, and opacities determined using about 130 UVIS stellar occultations over a wide range of viewing angles.
Enceladus plume occultation
On March 11, 2016, Enceladus passed in front of Epsilon Orionis (the central star in Orion’s Belt), and UVIS watched as the light from the star was altered as it passed through the plume. Such observations, known as stellar occultations, provide information about the density and composition of the plume.
The bright haloes in Saturn’s Rings