Details

Autor(en) / Beteiligte

• Kolvoord, Robert Andrew

Titel

Saturn's F ring: Imaging and simulation

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

1990

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The narrow width of Saturn's F ring belies its dynamical complexity. The kinks, clumps and braids discovered by the Voyager spacecraft give the ring an ever-changing appearance when viewed at different times or from different orientations. In an attempt to quantify the longitudinal variations in the F ring, I have examined a suite of Voyager 1 and 2 images of the F ring in detail, using a Fast Fourier Transform (FFT), to identify the periodicities present as a function of azimuthal extent. The results of this work show a small and well-defined set of periodic signals that can be interpreted as implying the presence of a few previously unseen small moonlets abutting the ring, in addition to Prometheus and Pandora, the F ring "shepherds". Complementary to the imaging results, I model the perturbations of a prototypical narrow planetary ring by nearby satellites using Gauss' equations for both two- and three-dimensions in hope of understanding the evolutionary mechanisms needed to create the variety of features observed in the ring. The dynamical simulation includes small satellites inside, amidst, and outside the ring proper, orbiting for many synodic periods. These simulations are animated to provide better insight into the temporally varying nature of the induced phenomena. Non-planar trajectories for both the ring particles and the local perturbers are also examined. While no evidence for braiding is apparent in any of these models, the importance of the relative positions of the various perturbers is demonstrated. Collisions are also included in a probabilistic sense, demonstrating the efficiency with which they can damp out periodic structure in the ring, and hence the limited longevity of imposed features in the system. The simulations, when examined using an FFT, show periodicities similar to those exhibited in the imaging study, when satellites with similar orbits to those around the actual F ring are used as perturbers. A detailed understanding of the interactions between rings and their nearby satellites will help us better understand both planetary rings and their analog, the protoplanetary nebula, from which the planets in our solar system formed.