Published in American Astronomical Society, DDA meeting
The edges of the Keeler and Encke gaps of Saturn's A Ring are significantly disturbed as the embedded moons (Daphnis and Pan, respectively) interact with the adjacent dense rings. Cassini images of these edges reveal the structure to be much more complex than predicted by analytical perturbation theory (Tiscareno et al 2005, DPS). In the Encke Gap,...
Published in American Astronomical Society, DDA meeting
We have carried out a comprehensive survey of the best Cassini ISS data of Saturn s main rings for the purpose of cataloguing all observed spiral density waves, spiral bending waves, and other radial and quasi-radial ring structure. Our survey has revealed a number of new features, including the first known resonant waves raised by Enceladus and Hy...
Published in American Astronomical Society, DDA meeting
We conducted numerical simulations of 3,830 massless test particles in the Saturn system near the 7: 6 corotation eccentricity resonance (CER) with Mimas, in response to the recent observations of an arc in the faint and dusty G Ring (see Hedman et al, this conference). We simulated 80 years of evolution, taking into account the perturbations of Sa...
Published in American Astronomical Society, DDA meeting
Cassini observations have shown that Saturn's tenuous E Ring has a double-banded vertical structure, with the density of particles decreasing in the equatorial plane of the rings. We have conducted numerical simulations, using SWIFT, supported by order-of-magnitude analytical calculations, to investigate how the micron-sized ice particles behave in...
Published in American Astronomical Society, DDA meeting
Using images taken by the Cassini spacecraft, we have identified a longitudinally confined arc of material located at the G ring's inner edge that is roughly five times brighter than other parts of the G ring. Images taken over the last two years show that the orbital mean motion of the arc is 445.475 +/- 0.007 degrees/day, corresponding to a semi-...
Published in American Astronomical Society, DDA meeting
Images from the Cassini spacecraft reveal several unexpected structures in Saturn s faint rings that appear to be generated by Lindblad resonances. The clearest example of such a feature consists of a series of brightness in the outer part of the diffuse G ring that appear to be generated by the 8: 7 Inner Lindblad Resonance with Saturn s moon Mima...
Published in American Astronomical Society, DDA meeting
In 2009 July, close to Saturn equinox, an isolated shadow-casting object was imaged in Saturn's B-ring at an orbital radius of about 116910 km. Spitale and Porco (2010, AJ) interpreted it as an embedded satellite, whose diameter, inferred by the length of the shadow, would have been 300 m. Although the object does not appear in any other images, wh...
Published in American Astronomical Society, DDA meeting
Moons embedded in planetary-ring gaps generate radial waves on the gap-edges. The scale and morphology of these waves can be used to deduce properties of the moons, particularly their masses. However, existing analytic theory describing the relationship between the moon s mass and the edge-wave amplitudes neglects non-linear effects during encounte...
Published in American Astronomical Society, DDA meeting
(2,250 Maximum Characters): The orbital elements of Saturn s moons are a moving target. Not only do they change with time due to gravitational interactions among the moons, but the familiar osculating elements are often not physically meaningful because of Saturn s large oblateness. Starting with numerical orbit integrations constrained by ground-b...
Published in American Astronomical Society, DDA meeting
The "propeller" moons within Saturn's rings are the first objects ever to have their orbits tracked while embedded in a disk, rather than moving through empty space (Tiscareno et al. 2010, ApJL). The km-sized "giant propellers" whose orbits have been tracked in the outer-A ring, as well as their smaller 0.1-km-sized brethren swarming in the mid-A r...
