Keck near-infrared observations of Saturnʹs E and G rings during Earthʹs ring plane crossing in August 1995

We present near-infrared (1.24–2.26 μm) images of Saturnʹs E and G rings which were taken with the W.M. Keck telescope in 1995 August 9–11, during the period that Earth crossed Saturnʹs 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 ringʹs 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 Jupiterʹs main ring, indicative of a (more typical) broad particle size distribution.