scholarly journals Origin and Evolution of Saturn’s Rings

1983 ◽  
Vol 6 ◽  
pp. 435-442
Author(s):  
G.E. Morfill

AbstractThe formation of planetary rings is discussed in the context of formation theories of the gaseous planets. The subsequent evolution of Saturn’s ring system, both dynamically and mechanically, is described, and the consequences are compared with observations.

1984 ◽  
Vol 75 ◽  
pp. 49-55 ◽  
Author(s):  
Steven J . Ostro ◽  
Gordon H. Pettengill

Saturn’s rings are the most distant radar-detected planetary entity, and the only radar-detected ring system. Neither distinction is likely to be reinquished during this century.Ten years have passed since the initial detection of radar echoes from Saturn’s rings (Goldstein and Morris, 1973) shattered prevailing notions that typical ring particles were 0.1 to 1 mm in size. (The single fact that microwave radar echoes are detectable requires a substantial density of particles larger than about one centimeter.) During the past decade, additional radar studies of the rings have been conducted, using the λ13.5-cm and λ12.6-cm systems at the Jet Propulsion Laboratory’s Goldstone Tracking Station and the λ112.6-cm system at the National Astronomy and Ionosphere Center’s Arecibo Observatory.


1984 ◽  
Vol 75 ◽  
pp. 393-395
Author(s):  
Richard J. Terrile

The Voyager encounters have provided the first high resolution look at the Saturn ring system. Images of the rings reveal several classes of dynamical processes active in creating and maintaining large scale structure. These classes include variable ring features attributable to the influence of external satellite resonances, ring structure induced by the shepherding effects from external and possibly internal satellites, smooth eccentric ringlets contained within clear gaps in the ring and the dynamics of spokes which may represent a transient ring atmosphere.


1984 ◽  
Vol 75 ◽  
pp. 763-767
Author(s):  
E.C. Stone

ABSTRACTIn the past five years ring systems have been discovered around Uranus and Jupiter and a wealth of new data acquired about Saturn’s rings. This vigorous observational program has been accompanied by renewed theoretical interest in ring systems. Although all of these topics have been addressed in papers at this first conference on planetary rings, these concluding remarks are focused on some of the key aspects of Saturn’s rings about which more needs to be understood through further data analysis, calculations, and observations.


In a former paper, the effect of satellites in producing divisions in Saturn’s Rings was discussed. The case taken was that where the satellite orbit and the rings were co-planar. The results afforded an explanation of the outer dimension of the Ring, Cassini’s Division, the inner radius of the bright ring, and the existence of the Crêpe Ring. But no reason was given for the existence of Encke’s Division, nor the numerous divisions reported by Lowell. In carrying the examination further, the fact that the satellite orbits are not precisely co-planar with the ring system must be considered. As given by the ‘Annuaire du Bureau des Longitudes,’ the inclination of the plane of the rings to the ecliptic is 28° 5·6', while the corresponding inclinations of the satellite orbits are— Mimas . . . . . . 27° 29·6', Dione . . . . . . 28° 4·4', Encelad us . . . 28° 4·3', Rhea . . . . . . 28° 22·8', Tethys . . . . . . 28° 40·5', Titan . . . . . . . 27° 39·7'. In the cases of Mimas, Tethys, and Titan, the differences are distinctly marked, the first being 36', or 0·01 of a radian. The effect of this inclination is examined in the sequel.


1984 ◽  
Vol 75 ◽  
pp. 739-742
Author(s):  
André Brahic

AbstractObservations of Saturn’s ring by Voyager spacecrafts have revealed a much more complex system than expected. So many basical physical meehanisms are involved that more data are required. The logical next step after Voyager is the launch of an orbiter around Saturn. Significant improvements of our knowledge about the ring system could be obtained with the highest possible resolution, with observations with a large variety otf phase angles, with multiple occultation experiments, with observations of the evolution of selected area with time, and with observations of small particles phenomena and electromagnetic properties of the spokes.


Author(s):  
Larry W. Esposito

Saturn’s rings are not only a beautiful and enduring symbol of space, but astronomers’ best local laboratory for studying phenomena in thin cosmic disks like those where planets formed. All the giant planets have ring systems. Saturn’s are the biggest and brightest. Saturn’s rings are made of innumerable icy particles, ranging from the size of dust to that of football stadiums. Galileo discovered Saturn’s rings with his newly invented telescope, but they were not explained until Huygens described them as thin, flat disks surrounding the planet. In the space age, rings were found around the other giant planets in our solar system. Rings have been seen around asteroids and likely exist around exoplanets. Many of the ring structures seen are created by gravity from Saturn’s moons. Rings show both ongoing aggregation and disaggregation. After decades of study from space and by theoretical analysis, some puzzles still remain unexplained. There is evidence for youthful rings from Cassini results, but no good theory to explain their recent origin. A future Saturn Ring Observer mission would be able to determine the direct connections between the individual ring physical properties and the origin and evolution of larger structures.


1991 ◽  
Vol 126 ◽  
pp. 357-360
Author(s):  
Laurance R. Doyle ◽  
Eberhard Grün

AbstractThe micron-sized dust forming the radial spoke-like features in Saturn’s rings are studied using radiative transfer analysis. Theories for their likely origin and evolution are discussed in light of these results, and future work is outlined.


1984 ◽  
Vol 75 ◽  
pp. 407-422
Author(s):  
William K. Hartmann

ABSTRACTThe nature of collisions within ring systems is reviewed with emphasis on Saturn's rings. The particles may have coherent icy cores and less coherent granular or frosty surface layers, consistent with thermal eclipse observations. Present-day collisions of such ring particles do not cause catastrophic fragmentation of the particles, although some minor surface erosion and reaccretion is possible. Evolution by collisional fragmentation is thus not as important as in the asteroid belt.


1984 ◽  
Vol 75 ◽  
pp. 265-277
Author(s):  
J.B. Holbelg ◽  
W.T. Forrester

ABSTRACTDuring the Voyager 1 and 2 Saturn encounters the ultraviolet spectrometers observed three separate stellar occultations by Saturn's rings. Together these three observations, which sampled the optical depth of the rings at resolutions from 3 to 6 km. can be used to establish a highly accurate distance scale allowing the identification of numerous ring features associated with resonances due to exterior satellites. Three separate observations of an eccentric ringlet near the location of the Titan apsidal resonance are discussed along with other ringlet-resonance associations occurring in the C ring. Density waves occurring in the A and B rings are reviewed and a detailed discussion of the analysis of one of these features is presented.


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