Self-gravity wakes and radial structure of Saturn's B ring

• Published in: Icarus (New York, N.Y. 1962) N.Y. 1962), 2007-09, Vol.190 (1), p.127-144
• Main Authors: Colwell, J.E., Esposito, L.W., Sremčević, M., Stewart, G.R., McClintock, W.E.
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Planetary rings; rings; Saturn; Solar system
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2007.03.018

We analyze stellar occultations by Saturn's rings observed with the Cassini Ultraviolet Imaging Spectrograph and find large variations in the apparent normal optical depth of the B ring with viewing angle. The line-of-sight optical depth is roughly independent of the viewing angle out of the ring plane so that optical depth is independent of the path length of the line-of-sight. This suggests the ring is composed of virtually opaque clumps separated by nearly transparent gaps, with the relative abundance of clumps and gaps controlling the observed optical depth. The observations can be explained with a model of self-gravity wakes like those observed in the A ring. These trailing spiral density enhancements are due to the competing processes of self-gravitational accretion of ring particles and Kepler shear. The B ring wakes are flatter and more closely packed than their neighbors in the A ring, with height-to-width ratios