Tiscareno, M.S., Burns, J.A., Sremcevic, M., Beurle, K., Hedman, M.M., Cooper, N.J., Milano, A.J., Evans, M.W., Porco, C.C., Spitale, J.N., Weiss, J.W. (2010). "Propellers in Saturn's Rings: Direct Observations of Disk-Embedded Masses" American Astronomical Society, DDA meeting #41, #11.01.


Abstract
"Propeller"-shaped structures, which surround unseen embedded moonlets in Saturn's A Ring (Tiscareno et al. 2006, Nature; Sremcevic et al. 2007, Nature; Tiscareno et al. 2008, AJ), have been individually tracked over the 5-year duration of the Cassini mission. In several cases, we confirm the persistence of individual disk-embedded moons over that span of time. Thus, for the first time, we are studying the long-term orbits of objects embedded in a disk, rather than orbiting in empty space. In at least one case, we see evidence of orbital evolution. Among the possible explanations for this orbital evolution, we find the most likely to involve gravitational and/or collisional interactions between the moon and the disk.