LAUSR

Abstract In this paper, we continue our analysis of the saturnian ring opposition effect seen by Cassini ISS. The ring opposition effect is a peak in the rings’ reflectivity caused as the directions from a spot on the rings to the observer and to the light source, respectively, converge toward zero degrees. So far, the exact origin of the ring’s opposition effect is still a matter of debate. In our previous work (Deau, et al., 2013, Icarus, 226, 591–603), we compared the opposition effect morphology with the rings’ optical depth and found that only the slope of the linear part of the rings’ phase curves was strongly correlated with the optical depth. We interpreted this as an indication of the predominant role of interparticle shadowing at moderate phase angles (α ∼ 10–40o). More recently (Deau, 2015, Icarus, 253, 311–345), we showed that interparticle shadowing cannot explain the behavior at low phase angles (α