DPS 35th Meeting, 1-6 September 2003
Session 11. Planetary Rings I
Oral, Chairs: L. Spilker and C. B. Olkin, Wednesday, September 3, 2003, 1:30-3:00pm, DeAnza III

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[11.01] Collisional Formation of Arcs in Narrow Rings

M. C. Lewis (Trinity University), G. R. Stewart (Laboratory for Atmospheric and Space Physics)

We present the results of simulations showing that the formation of stable arcs in narrow rings perturbed by a single eccentric perturber is to be expected. We have been performing simulations of a system resembling Saturnís F ring with a Prometheus like perturber. The ring is circular, but the moon is on an eccentric orbit. We find that in some of these simulations the ring material begins to group in azimuthally confined regions that resemble arcs. This type of behavior had been seen by Showalter and Burns (Icarus 1982) but without collisions it is transient. In our simulations, it is longer lived because collisions prevent the particles from smoothly shearing past one another. The material gathers around the point where the previous perturbation from the moon was smallest (greatest separation from the moon). The arcs are stable and maintain a phase difference with respect to the moon's apocenter if the ring is in resonance with the moon. Outside of resonance, the arcs will eventually be torn apart when they pass the moon at the point of smallest separation. We would not expect to see this in the F ring, even if in resonance, because of the presence of Pandora. It can only be stable when the ring is in resonance with a single perturbing moon. We would like to acknowledge support from NASA's Planetary Geology and Geophysics research program.

The author(s) of this abstract have provided an email address for comments about the abstract: mlewis@trinity.edu

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.