Exploring overstabilities in Saturn's A ring using two stellar occultations

Abstract

Certain regions of Saturn's rings exhibit periodic opacity variations with characteristic radial wavelengths of up to a few hundred meters that have been attributed to viscous overstabilities. The Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft observed two stellar occultations of the star gamma Crucis that had sufficient resolution to discern a sub-set of these periodic patterns in a portion of the A ring between 124,000 and 125,000 km from Saturn center. These data reveal that the wavelengths and intensities of the patterns vary systematically across this region, but that these parameters are not strictly determined by the ring's average optical depth. Furthermore, our observations indicate that these opacity variations have an azimuthal coherence scale of around 3000 km.

11 Pages, 11 Figures, updated to include small typographical corrections found in proofs

References in corpus (5)

• Cassini Imaging of Saturn's Rings II: A Wavelet Technique for Analysis of Density Waves and Other Radial Structure in the Rings
• Kronoseismology: Using density waves in Saturn's C ring to probe the planet's interior
• Large-scale N-body simulations of the viscous overstability in Saturn's rings
• The viscous overstability, nonlinear wavetrains, and finescale structure in dense planetary rings
• Hydrodynamical simulations of viscous overstability in Saturn's rings

Cited by in corpus (8)

• The B-ring's surface mass density from hidden density waves: Less than meets the eye?
• Numerical Simulations of Saturn's B Ring: Granular Friction as a Mediator between Self-Gravity and Viscous Overstability
• Incomplete cooling down of Saturn's A ring at solar equinox: Implication for seasonal thermal inertia and internal structure of ring particles
• Occultation observations of Saturn's rings with Cassini VIMS
• Density Waves and the Viscous Overstability in Saturn's Rings
• Viscous Overstability in Saturn's Rings: Influence of Collective Self-gravity
• A Weakly Nonlinear Model for the Damping of Resonantly Forced Density Waves in Dense Planetary Rings
• Filament formation due to diffusive instabilities in dusty protoplanetary disks