Expectations for Cassini observations of ring material with nearby moons

Lewis, Marc D.; Stewart, G. R.

doi:10.1016/j.icarus.2005.04.009

Cited by 26 publications

(15 citation statements)

References 43 publications

(55 reference statements)

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“…These large rubble piles are indeed dynamic and are very different from the simple idea of spherical ring particles of a uniform size. In the outer regions of Saturn's rings temporary aggregations are typically elongated and sheared, as seen in numerical simulations (e.g., Salo 1995;Lewis and Stewart 2005) and in various measurements (e.g., Colwell et al, 2007) of the self-gravity wakes in the A Ring, as well as one partially transparent F Ring feature ("Pywacket") observed by the Cassini UVIS and VIMS instruments (Esposito et al, 2008a).…”

Section: Ring Particle Sizesmentioning

confidence: 66%

Origin and Evolution of Saturn's Ring System

Charnoz

Dones

Esposito

et al. 2009

Saturn From Cassini-Huygens

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ABSTRACT:The origin and long-term evolution of Saturn's rings is still an unsolved problem in modern planetary science. In this chapter we review the current state of our knowledge on this longstanding question for the main rings (A, Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During the Voyager era, models of evolutionary processes affecting the rings on long time scales (erosion, viscous spreading, accretion, ballistic transport, etc.) had suggested that Saturn's rings are not older than 10 8 years. In addition, Saturn's large system of diffuse rings has been thought to be the result of material loss from one or more of Saturn's satellites. In the Cassini era, high spatial and spectral resolution data have allowed progress to be made on some of these questions. Discoveries such as the "propellers" in the A ring, the shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus' plume provide new constraints on evolutionary processes in Saturn's rings. At the same time, advances in numerical simulations over the last 20 years have opened the way to realistic models of the rings' fine scale structure, and progress in our understanding of the formation of the Solar System provides a better-defined historical context in which to understand ring formation. All these elements have important implications for the origin and long-term evolution of Saturn's rings. They strengthen the idea that Saturn's rings are very dynamical and rapidly evolving, while new arguments suggest that the rings could be older than previously believed, provided that they are regularly renewed. Key evolutionary processes, timescales and possible scenarios for the rings' origin are reviewed in the light of these recent advances.

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Section: Ring Particle Sizesmentioning

confidence: 66%

Origin and Evolution of Saturn's Ring System

Charnoz

Dones

Esposito

et al. 2009

Saturn From Cassini-Huygens

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“…Disaggregation by disruptive collisions or tidal shedding (7) may follow. Images and occultations show broad swaths of "straw" in the innermost troughs between crests of strong spiral density waves (SOM text 7) and adjacent to the Encke gap edge (19,35). These clumps of "straw," probably formed by packing in the dense wave crests, are kilometers to tens of kilometers in extent.…”

Section: Packing In Compressed Regionsmentioning

confidence: 99%

“…If the moonlet's orbit is sufficiently eccentric, or very close to the gap edge, nonlinear effects modify this result slightly (34,35). Collisions should cause the wavy edges to decay downstream, but the Encke edge's undulations persist around the full circumference, exhibiting the expected period and several others, too [see the figure in (36), taken from (37)].…”

Section: Embedded Moonletsmentioning

confidence: 99%

“…The finite volumes of ring particles can also cause the ring material to "splash" vertically (SOM text 4) when compressed. Diverse particle orbits can be jammed into synchronized trajectories such that limited radial regions may orbit as units rather than with the normal Keplerian shear, reducing viscous dissipation and differential precession, and perhaps even creating large, clumpy structures (35) (SOM text 7). Disaggregation by disruptive collisions or tidal shedding (7) may follow.…”

Section: Packing In Compressed Regionsmentioning

confidence: 99%

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An Evolving View of Saturn’s Dynamic Rings

Cuzzi

Burns

Charnoz

et al. 2010

Science

127

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We review our understanding of Saturn's rings after nearly 6 years of observations by the Cassini spacecraft. Saturn's rings are composed mostly of water ice but also contain an undetermined reddish contaminant. The rings exhibit a range of structure across many spatial scales; some of this involves the interplay of the fluid nature and the self-gravity of innumerable orbiting centimeter- to meter-sized particles, and the effects of several peripheral and embedded moonlets, but much remains unexplained. A few aspects of ring structure change on time scales as short as days. It remains unclear whether the vigorous evolutionary processes to which the rings are subject imply a much younger age than that of the solar system. Processes on view at Saturn have parallels in circumstellar disks.

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“…The elasticity of particle impacts is described by the normal coefficient of restitution n , specifying the ratio of the post-and pre-4 Lewis and Stewart (2005) have demonstrated that the interplay of satellite forcing and ring self-gravity can lead to larger radial scales, probably accounting for the kilometer-sized wakes seen near the edge of the Encke gap (Porco et al, 2005). collisional relative velocity components in the direction joining the particle centers.…”

Section: Dynamical Models Of Gravity Wakesmentioning

confidence: 99%