Burns, J. A., Tiscareno, M. S., Spitale, J., Porco, C. C., Cooper, N. J., Beurle, K. (2008). "Giant Propellers Outside the Encke Gap in Saturn's Rings" American Astronomical Society, DPS meeting #40, #30.07.

Propeller-shaped disturbances occur in Saturn's rings as a result of small moonlets, tens to hundreds of meters in diameter, embedded in the rings (Tiscareno et al. 2006, Nature). These propellers are most abundant in a 3,000-km-wide belt in the mid-A Ring (Sremcevic et al. 2007, Nature). A detailed analysis of this population was given by Tiscareno et al (2008, AJ).

Here we report observations of five new propellers, all of which are larger than the largest previously known. All five of these are found in multiple, widely-separated apparitions, allowing us for the first time to investigate the longevity and orbital stability of propellers. These new propellers all occur exterior to the Encke Gap, farther from Saturn than the population in the propeller-rich belt, and the larger sizes are likely in part enabled by the larger Hill sphere of any individual seed. The larger sizes also permit a more detailed view of propeller morphology; for the first time, both dark and bright components of the propeller structure are discernible.

Note: This presentation will actually be given as an oral talk, in place of #21.06 by Tiscareno et al. A poster containing the latter presentation will appear here, in the Late Poster session.