The Shape of Saturn's A Ring Edge from Cassini VIMS, UVIS, and RSS Occultations
Abstract
The shape of the outer edge of Saturn's A ring is strongly affected by the nearby coorbital satellites Janus and Epimetheus, which swap their relative positions every four years due to mutual gravitational interactions. When Janus is located at its inner position, its 7:6 inner Lindblad resonance lies very near to the A ring outer edge, producing a ~12-km amplitude 7-lobed distortion. This pattern disappears when Janus moves to the outer position. In addition to this prominent forced m=7 mode, a number of weaker free normal modes with wavenumbers ranging between 3 and 18 have been observed intermittently. Over the course of the Cassini mission (2005-2017), the coorbital swap has taken place several times. Using a comprehensive set of Cassini VIMS, UVIS and RSS ring occultation observations, we characterize the time-varying disappearance and reappearance of these recognizable components of the complex shape of the A ring edge.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P23C3510M
- 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