Science Seminars

5/21/2015 – Saturn Seismology: complex interactions between the planet, the rings, and the moons

Speaker: Jim Fuller (Caltech)
Date: Thursday, May 21, 2020
Time: 4:00 PM
Location: LSTB A299

Seminar Abstract:

The rich dynamics of the Saturn ring and moon systems offer unique opportunities to study the evolution of the planet and its surrounding bodies. For instance, seismology of Saturn is made possible by the gravitational interaction between Saturn and its rings, in which density waves in the rings are excited by Lindblad resonances with Saturn’s oscillation modes. The seismic signatures in the rings suggest the existence of stable stratification in the deep interior of the planet, likely created by composition gradients between the core and envelope due to helium sedimentation and/or core erosion. These structures within the planet may in turn influence the tidal interactions which drive the outward migration of Saturn’s inner satellites. The moons may become trapped in resonances with Saturn’s gravity modes, forcing the moons to migrate outward on a planetary evolution timescale and capturing outer moons in mean motion resonances as their orbits expand. The eccentricity of Enceladus is excited by resonance with Dione, generating tidal heating and geysers that replenish the E-ring, completing the circle of interaction between planet, moons, and rings.