Spitale, J. N., Porco, C. C., Baker, E., Tiscareno, M., Burns, J. A. (2005). "Cassini Imaging of Noncircular Features in Saturn's Rings." American Astronomical Society, DPS meeting #37, #66.01.

We report on our initial examination of some of the eccentric features in Saturn's rings observed in Cassini imaging sequences. High-resolution movies and 360-degree azimuthal imaging scans, with radial spatial scales as fine as a few km and longitudinal resolutions as fine as a fraction of a degree, reveal the shapes of these features in great detail. The outer edges of the B ring, anchored by the strongest resonance in Saturn's rings -- the Mimas 2:1 inner Lindblad resonance (ILR) -- shows high-frequency radial departures from a simple m=2 shape, as previously found in Voyager data [1] but now seen with greater precision. The outer edge of the A ring, controlled by the Janus/Epimetheus 7:6 ILR, also appears to depart from the simple m=7 sinusoidal shape expected for this model [1]. High- spatial-frequency azimuthal variability has also been seen in other ring edges throughout the rings and in greater detail in the known narrow eccentric ringlets inhabiting the gaps in Saturn's rings, such as the Huygens gap exterior to the B ring and the Maxwell gap in the C ring, and in newly discovered, more tenuous rings seen in these gaps. The shape of the F-ring core is largely consistent with that determined by Bosh et al. [2], though at fine scales it is highly time-variable (see Chavez et al. and Charnoz et al., this conference).
[1] Porco et al., 1984, Icarus 60, 17. [2] Bosh et al., 2002, Icarus 157, 57.