The dark side of Saturn's rings: Comparing eclipse observations from Cassini
Abstract
Three times over the past 7 years, Cassini has passed through Saturn's shadow and obtained spectacular mosaics of Saturn's rings backlit by the Sun. Beyond providing some of the most striking images from the mission, these observations yield unique information about Saturn's most tenuous rings, including the D, E and G rings. The small particles that dominate the optical cross section of these rings scatter light most efficiently in these backlit viewing geometries, so these eclipse events allow us to detect and characterize extremely faint ringlets that are nearly impossible to detect at any other time. For example, we can clearly see ringlets associated with several small moons like Pallene and Janus, which are likely composed of debris knock off these moons by meteoroid impacts. These eclipse observations also contain unique information about the large-scale structure of Saturn's E ring. This broad ring is derived from Enceladus' plume, but also exhibits puzzling longitudinal asymmetries in its brightness and color that are likely due to non-gravitational perturbations acting on the tiny ring particles. Differences among the eclipse observations from 2006, 2012 and 2013, which were obtained at different seasons and solar illumination conditions, should permit a better understanding the forces sculpting this ring.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.P23D1816H
- Keywords:
-
- 5759 PLANETARY SCIENCES: FLUID PLANETS Rings and dust