An Inclined Saturnian Ringlet at 1.954 Rs
Abstract
Cassini ISS Imaging and UVIS occultation observations of the narrow ringlet centered at 1.954 Rs, near the outer edge of the Huygens gap, can best be explained if the ringlet deviates significantly from the mean ring plane. In ISS images taken at very low elevation angles, the ringlet consistently appears non-concentric with nearby ring material, while in UVIS occultations it sometimes appears superimposed on material outside the gap. The in-plane shape of the ringlet, as determined from high-elevation ISS images, is a freely-precessing Keplerian ellipse ranging in orbital radius between 117890 and 117920 km, well inside the gap, so the UVIS result must arise from the geometric projection of material elevated above the ring plane. The ringlet extends at least 8 km out of the ring plane, but we are unable to fit a simple inclined model to the observations, suggesting that the ringlet's vertical shape is complicated. In addition to its vertical structure, the ringlet is clumpy and discontinuous, with significant in-plane deviations from its basic elliptical shape. There are no obvious resonant perturbations from known satellites though association with one or more small, embedded and still unseen satellites may be possible.
We acknowledge the financial support of the Cassini Project.- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #40
- Pub Date:
- September 2008
- Bibcode:
- 2008DPS....40.2102S