Tiscareno, M., Hedman, M. M., Burns, J. A., and Nicholson, P. D. (2007). "Numerical Simulations of the G Ring Arc." American Astronomical Society, DDA meeting #38, #12.03.
We conducted numerical simulations of 3,830 massless test particles in the Saturn system near the 7:6 corotation eccentricity resonance (CER) with Mimas, in response to the recent observations of an arc in the faint and dusty G Ring (see Hedman et al, this conference). We simulated 80 years of evolution, taking into account the perturbations of Saturn's nine most massive moons, the Sun, Jupiter, and Saturn's J2 and J4 gravity harmonics. Perturber trajectories were obtained at every timestep from JPL ephemera DE414 and SAT252.|
We find that particles are efficiently trapped into librations about any of the six corotation sites, consistent with the observed arc which extends 30 degrees in longitude. We find forced eccentricities that are consistent with the observed radial width of the arc, and a long libration period (1273 days) which indicates we may have yet to observe the turning point in the arc's libration.
The potentially disruptive effects of inter-particle collisions were not taken into account, due to the G Ring's very low optical depth. Leakage out of the resonance is probably dominated instead by non-gravitational forces, which preferentially drive smaller (dust) grains outward, plausibly accounting for the observed radial profile of the G Ring.