The Leonard E Parker Center for Gravitation, Cosmology and Astrophysics holds frequent seminars on a broad range of ongoing cosmology and gravitation research topics. Unless otherwise noted, seminars are on Friday afternoons at 1:00 PM in KIRC 2175; there is a gathering for a brown bag lunch at 12:30.

Measuring the Vertical Structure of the F Ring of Saturn
Dr. Britt Scharringhausen, Beloit College

Saturn’s narrow, dusty F ring lies just outside the main rings. It is difficult to observe from Earth, except during a ring-plane crossing, when the rings are viewed edge-on. These events occur only about every 15 years. In a ring-plane crossing observed by Hubble Space Telescope in August 1995, an asymmetry in brightness between the east and west sides of the rings was observed. We have shown that the inclination of the F ring relative to the main rings caused the asymmetry, because the F ring can obscure the east and west side of the main rings to different extents. This discovery afforded an opportunity to measure the vertical thickness of the F ring, which we found to be 13 +/- 7 km. Since 2004, the F ring has been observed extensively by the Cassini spacecraft, and since Cassini crosses the ring-plane twice each orbit, several ring-plane crossings have been observed. We apply the same techniques used to analyze the Earth ring-plane crossing to the best of these observations, which was made Dec 1-2, 2005. Finer resolution and more rapid sampling allows us to probe the vertical structure of the F ring in much greater detail.