Saturn’s rings are an accessible exemplar of an astrophysical disk, tracing the Saturn system’s dynamical processes and history. We present close-range remote-sensing observations of the main rings from the Cassini spacecraft. We find detailed sculpting of the rings by embedded masses, and banded texture belts throughout the rings. Saturn-orbiting streams of material impact the F ring. There are fine-scaled correlations among optical depth, spectral properties, and temperature in the B ring, but anticorrelations within strong density waves in the A ring. There is no spectral distinction between plateaux and the rest of the C ring, whereas the region outward of the Keeler gap is spectrally distinct from nearby regions.
The rings are sculpted by embedded masses, producing structure visible down to our resolution limit. Correlations of spectral properties and temperature with optical depth are tight at many locations, although exceptions are found that deepen puzzles in certain regions. Many of these results are likely related to radial stratification in particle properties, rather than in chemical composition or surface mass density. https://science.sciencemag.org/content/364/6445/eaau1017.abstract
Close-range remote sensing of Saturn’s rings during Cassini’s ring-grazing orbits and Grand Finale
False-color images of Saturn’s rings.
(Top) A mosaic showing Daphnis in the Keeler gap on the lit side of the rings, with three wave crests of the structure raised by Daphnis in the gap’s outer edge. (Middle and bottom) Visual and Infrared Mapping Spectrometer radial scans across the lit side of the main rings, displayed as false-color images. Reddish colors signify a higher fraction of components other than water ice. The boxed region in the middle panel indicates the location of the bottom panel.
MAQ Magazine n. 13 / July 2019