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A. Brahic, S. Charnoz, K. Baillie (Universite Paris 7 / CEA Saclay), C. Porcco (CICLOPS / SSI)
Recent CASSINI ISS observations have shown that the "strands" of the Saturn's F ring may be understood as a single spiral arm (Charnoz et al, this conference). A simple dynamical model is presented here to explain the origin of this structure. The close encounter of a satellite with a ringlet is simulated. When the satellite and the ringlets are close enough, the ringlet is fragmented in pieces which are scattered around. Due to keplerian shear, each fragment spreads with time. After one year evolution (which is many orbital periods of the F ring particles), one trailing and radially evolving spiral arm is observed; successive interactions with the satellite destroy the spiral after two years. In other words, the spiral is constantly created and destroyed. This model, in which F ring strands form a single and dynamically evolving structure, seems to be in good agreement with the imaging observations. Prometheus may not be the responsible moon or the only responsible moon. Other possible candidate satellites are also discussed.
The author(s) of this abstract have provided an email address for comments about the abstract: charnoz@cea.fr
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.