[Previous] | [Session 33] | [Next]
K. Ohtsuki (U. Colorado)
Voyager data on Saturn's rings have greatly advanced our knowledge of the particle size distribution. Understanding the evolution of the size distribution would constrain the origin and evolution of the rings, and it can also let us estimate abundance of unseen large moonlets, which would be responsible for many observed features in ring systems, such as those observed in Saturn's F ring. In the present work, we study the evolution of particle random velocity due to mutual gravitational encounters and inelastic collisions, and the evolution of particle size distribution due to accretion. First, we calculate steady-state random velocities of ring particles with a given size distribution, using the velocity stirring rates based on the result of three-body orbital integrations. We confirm good agreement with the result of local N-body simulation. Next, using the velocity stirring and collision rates of ring particles based on three-body orbital integrations, we perform a statistical simulation of evolution of particle size distribution due to accretion. In the case of perfect accretion, we confirm good agreement with the result of local N-body simulation for ring particle accretion. We will also discuss the effect of tidally modified accretion in the Roche zone (Ohtsuki 1993, Icarus 106, 228), where particles which differ greatly in mass can gravitationally accrete more easily.
If the author provided an email address or URL for general inquiries,
it is as follows:
Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.