Keck near-infrared observations of Saturn's E and G rings during Earth's ring plane crossing in August 1995

We present near-infrared (1.24–2.26 μm) images of Saturn's E and G rings which were taken with the W.M. Keck telescope in 1995 August 9–11, during the period that Earth crossed Saturn's ring plane. Our data confirm that the E ring is very blue. Its radial and vertical structure are found to be remarkably similar to that apparent in the HST ringplane crossing data at visible wavelengths, reinforcing models of the ring's peculiar narrow or very steep particle size distribution. Our data show unambiguously that the satellite Tethys is a secondary source of material for the E ring. The G ring is found to be distinctly red, similar in color to Jupiter's main ring, indicative of a (more typical) broad particle size distribution.