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B. R. Scharringhausen, P. D. Nicholson (Cornell University)
We present a photometric model of Saturn's F ring in order to reproduce Hubble Space Telescope (HST) profiles of ring brightness vs. distance from Saturn during the 1995 ring-plane crossing. We also intend to model the change of brightness of the rings with time within a few hours of the ring-plane crossing.
When the rings are seen nearly edge-on, the vertically thick F ring is thought to dominate the brightness of the ring system (Nicholson et al. 1995 Science 272, 453). In order to reproduce the edge-on brightness of the rings, Poulet et al. (2000 Icarus, 145, 147) have modeled the F ring as an uninclined ribbon, ~ 21~km in vertical extent, with a uniform radial optical depth of ~0.02.
However, in HST images of the August and May 1995 ring-plane crossings, an asymmetry in the ring brightness between the east and west ansae was observed (Nicholson et al. 1995, Bosh et al. 1997 Icarus 129, 555.) In the edge-on geometry of the ring-plane crossing, an inclined F ring could block one ansa of the main rings more than the other, resulting in the asymmetry in the ring brightness.
To more accurately reproduce the observed ring brightness, our F ring model improves upon the model of Poulet et al. (2000) by including the non-zero inclination of the F ring (Bosh et al., Icarus, submitted) as well as by varying the radial optical depth as a function of height above or below the F ring plane.
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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.