Dynamics of Planetary Rings and Extrasolar Planets

Eugene Chiang
U.C. Berkeley

Planetary rings showcase a rich interplay
of forces due to interparticle collisions, self-gravity,
and the gravity of shepherd moons. They present miniature
versions of phenomena thought to occur in protoplanetary
disks: viscous dissipation, the clearing of annular gaps
by large bodies, and migration and eccentricity evolution.
I will focus on one longstanding problem in ring dynamics,
that of apsidal alignment: how an eccentric ring precesses
about the central planet as if it were a rigid body. 
I will demonstrate how forces due to collisions, self-gravity,
and the quadrupole field of the central planet can be
balanced to produce ring surface densities that agree
with Voyager spacecraft observations. I will then
magnify the dynamical stage to examine the apsidal
alignment exhibited by extrasolar planets orbiting
Upsilon Andromedae, and conclude with a novel explanation
for the uncommonly large eccentricities exhibited
by extrasolar systems.