Sizes of Particles and Highly Resolved Ring Structure in Saturn's Rings from an Analysis of Higher Order Statistical Moments of Cassini UVIS Stellar Occultation Data
Abstract
The high speed photometer (HSP) of Cassini's Ultraviolet Imaging Spectrograph (UVIS) observed 275 ring stellar occultations at unprecedented high resolution with a multitude of different viewing geometries, allowing an unparalleled view into the three-dimensional structure of the rings. We follow and expand on the methods of Showalter and Nicholson (1990) and Colwell et al. (2018) to develop a contemporary survey of higher order statistical moments across density and bending waves which originate from orbital resonances with nearby moons. These waves are particularly interesting because they reflect azimuthal variations in gravitational potential, which lead to small-scale variations in ring particle number density. We exploit the adherence of stellar occultation data to Poisson statistics to investigate the higher order statistical moments of excess variance, skewness, and kurtosis across these fine structures. We compare and contrast statistical moments from waves in different regions of the rings, particularly in the Janus 2:1, Janus 4:3, Pandora 5:4, and Mimas 5:3 density and bending waves, from a variety of occultations at different viewing geometries to develop a clearer picture of the rings to complement the predator-prey model described in Esposito et al. (2012) for ring particle aggregation. Finally, we combine our analysis of the data with Monte Carlo simulations of skewness versus optical depth, which have already revealed unique information about the presence of localized gaps, or 'ghosts', in the C ring, and consider what occultation statistics tell us about how density waves differ from other three-dimensional ring structures.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P23C3512E
- Keywords:
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- 6022 Impact phenomena;
- PLANETARY SCIENCES: COMETS AND SMALL BODIES;
- 6213 Dust;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6245 Meteors;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6265 Planetary rings;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS