Unveiled density wave in Saturn’s rings

Abstract

We unveil a two-dimensional visualization of the Mimas 5:3 density wave in Saturn’s rings, created directly from 31 radial optical depth profiles of the rings obtained between 2005 and 2008 from Cassini Radio Science Subsystem (RSS) occultation observations, assuming only its predicted pattern speed and taking advantage of its evident four-armed structure. Using a variety of interpolation and smoothing methods to combine the observations, the resulting image of the density wave is a striking confirmation of the expected wave properties based on dynamical theories. From measurements of the radial locations of the wave peaks and troughs, we measure the variation of wavenumber across the wave and use this information to compute the variable background surface density in the wave region. We are able to compute the angular momentum luminosity in the linear regime by two methods, using either the satellite potential or the observed optical depths. The two methods give results of the same order of magnitude.