Victor Afigbo

Major: Physics

Faculty Advisor: Matthew Hedman

Project Title:

What Makes Saturn Ring? A Quest to Quantify the Amplitudes of Saturn's Planetary Normal-mode Oscillations using Ring Seismology

Abstract

Certain spiral density waves in Saturn's rings are generated by resonances with planetary normal modes, and as a result, they can be used as probes of Saturn's internal structure. Previous works on these waves have focused mainly on their rotation rates, which have provided precise measurements of the oscillation frequencies of Saturn. However, there are other aspects of the waves that contain information about the planet's interior. Specifically, the amplitudes of the ring waves are determined by the amplitudes of the corresponding planetary normal modes. We have determined the amplitudes of the perturbing potentials responsible for generating dozens of waves by fitting high signal-to-noise profiles derived from Cassini's Visual and Infrared Mapping Spectrometer(VIMS) occultations. This yields a spectrum of mostly fundamental mode (f-mode) oscillations with relatively low spherical harmonic degree that can provide insights into how these sorts of oscillations are excited inside the planet.

Funding: NASA - Probe Saturn's Rings Project.