Burt, J.A., Hedman, M.M., Burns, J.A., Tiscareno, M.S. (2010). "Dynamical Analysis of the Heliotropic 'Charming' Ringlet located in Saturn's Cassini Division" American Astronomical Society, DDA meeting #41, #11.08.


Abstract
The "charming" ringlet is a low-optical depth, dusty ringlet located in the Laplace gap in the Cassini Division, roughly 119,940 km from Saturn's center. This ringlet is particularly interesting because it appears to be "heliotropic;" that is its center of light occurs further from Saturn's center at longitudes near local noon than it does at longitudes near local midnight. This behavior indicates that the dynamics of the particles in this ring are being influenced by solar radiation pressure.

To explore this phenomenon in detail, we analyze multiple image sequences of this ringlet obtained by Cassini in order to constrain its shape and orientation. These data can be fit reasonably well with a model in which both the eccentricity and the inclination of the ringlet have "forced" components (that maintain a fixed orientation relative to the Sun) as well as "free" components (that drift around the planet at a steady rate determined by Saturn's oblateness). While our observationally derived magnitude for the forced eccentricity is roughly consistent with theoretical expectations, the existence of significant free eccentricities and inclinations poses a significant challenge for models of low-optical-depth dusty rings.