Tidal breakup and origin of the Uranian ring system

1984 ◽  
Vol 75 ◽  
pp. 687-689
Author(s):  
P. Farinella ◽  
A. Milani ◽  
A.M. Nobili ◽  
P. Paolicchi
Keyword(s):  
Observational Data ◽  
Ring System ◽  
Dissipative Processes ◽  
Gravitational Torque ◽  
Gravitational Forces ◽  
Uranian Ring ◽  
Interparticle Collisions ◽  
Ring Material

The peculiar features of the Uranian ring system have posed several difficult dynamical problems. The mutual gravitational forces among the ring particles can ensure stability against the spreading due to differential precession of the orbits, but are not able to provide an effective confinement mechanism against dissipative processes like interparticle collisions (Farinella et al., 1978, 1980a). The existence of small undiscovered satellites inside the orbit of Miranda is not ruled out by the presently available observational data, and has been proposed by Goldreich and Tremaine (1979) as a possible solution for the confinement problem: each ring is supposed to lie between two different satellites exerting a gravitational torque which tends to repel ring material and prevents the collisional spreading.

Weak dynamical effects in the Uranian ring system

1984 ◽  
Vol 75 ◽  
pp. 457-458
Author(s):  
Adam P. Freedman ◽  
Scott Tremaine ◽  
James L. Elliot
Keyword(s):  
Close Association ◽  
Ring System ◽  
Convincing Evidence ◽  
Gravitational Forces ◽  
Ring Model ◽  
Maximum Change ◽  
Uranian Ring ◽  
The Masses ◽  
Three Body ◽  
Residual Errors

ABSTRACTA number of weak gravitational forces were examined for their kinematic effects on the Uranian ring system, in an attempt to account for residual errors of ~2 km in the ring positions and a few times 10-3deg/day in the apse precession rates. The principal conclusions are as follows: (1) perturbations by the five known satellites are too small to have observable effects with the best current estimates of the satellite masses. (2) Limits can be set on the masses of inter-ring “shepherd” satellites from their influence on precession rates and their radial perturbations on the rings. For example, the maximum mass of a shepherd satellite between rings 4 and 5 is ~ 1019gm. (3) Using the best available ring parameters, there is no convincing evidence that the rings are associated with resonances with known satellites. The only close association is of rings 5, α and γ with three-body resonances due to Miranda and Ariel. It is more likely that the putative shepherd satellites may occupy resonances. (4) The known satellites can cause anomalous residuals by changing the position of Uranus relative to the system barycenter during the occultation. The maximum change, so far, during the 1977 March 10 event, was 1.6 km. This effect will be investigated with the MIT Uranus ring model.

Voyager and the Origin of the Saturnian System

1981 ◽  
Vol 4 (2) ◽  
pp. 164-171 ◽  
Author(s):  
A. J. R. Prentice
Keyword(s):  
Magnetic Forces ◽  
Gravitational Forces ◽  
Keplerian Orbits ◽  
Saturnian System ◽  
Radial Spokes ◽  
The Law ◽  
Electro Magnetic ◽  
F Ring ◽  
Saturn's Rings ◽  
Interparticle Collisions

As Voyager 1 sailed through Saturn’s system of moons and rings last November 1980 it revealed new worlds not seen by man before. For centuries, since Galileo’s first telescopic observations in 1610, the satellites of Saturn had been no more than pin points of light, whilst the structure of the rings was barely resolved beyond 3 principal bands. Yet, within the space of a few hours, that picture changed dramatically as the images of these objects grew through Voyager’s cameras from mere specks into full and wondrous worlds. These pictures contained features that were not only intricate and astonishing in detail but which were, in many cases, unfamiliar and unexpected. A composite view of the Saturnian system as seen by Voyager 1 appears in Figure 1. Saturn’s rings, once thought to be broad belts of particles spread uniformly thin through billions of years of evolution and interparticle collisions, were found to be divided into hundreds of individual ringlets (Figure 2). And Cassini’s Division, a region which had been previously thought to be empty because of a ‘sweeping’ influence of Mimas, was found to contain many ringlets itself! The appearance of light and dark radial spokes in the B ring, which rotated with a velocity contrary to the law expected of Keplerian orbits, was baffling. And the F ring (Figure 3) was found to contain knots, kinks and braids which probably indicated the presence of electro-magnetic forces as well as gravitational forces (Smith et al. 1981).

The Evolution of Meteor Streams

1984 ◽  
Vol 75 ◽  
pp. 717-721
Author(s):  
Ken Fox ◽  
Iwan P. Williams
Keyword(s):  
Observational Data ◽  
Ring System ◽  
Meteor Stream ◽  
Ring Systems ◽  
Meteor Streams ◽  
Gravitational Perturbations ◽  
Considerable Period

If one regards a ring system as a family of particles moving on coherent orbits which may be influenced by the gravitational perturbations of a secondary.then a meteor stream is a good example of a ring system. Of course, there is a difference in that the eccentricity and inclination of meteor streams are significantly higherthan any found in ring systems about planets. Nevertheless, it may be instructive to consider briefly the evolution of meteor streams. One advantage of studying meteor streams is that observational data is available over a considerable period (at least 100 years in all cases and in excess of 1000 years for streams like the Perseids, Eta Aquarids and Orionids).

Dynamics of eccentric and inclined ringlets

1984 ◽  
Vol 75 ◽  
pp. 341-343
Author(s):  
N. Borderies ◽  
P. Goldreich ◽  
S. Tremaine
Keyword(s):  
Semimajor Axis ◽  
Ring System ◽  
The Self ◽  
Uranian Ring ◽  
Self Gravity

The Saturn and Uranian ring system contain a number of narrow eccentric ringlets. Several of the Uranian ringlets are also inclined to the planet's equator. We show that the self-gravity is probably responsible for maintaining apse and node alignment across these ringlets. This hypothesis leads to the prediction that within each ringlet both the eccentricity and the inclination increase with semimajor axis.

Weak dynamical effects in the Uranian ring system

1983 ◽  
Vol 88 ◽  
pp. 1053 ◽  
Author(s):  
A. P. Freedman ◽  
S. Tremaine ◽  
J. L. Elliot
Keyword(s):  
Ring System ◽  
Uranian Ring

scholarly journals 20. Positions and Motions of Minor Planets, Comets and Satellites

1982 ◽  
Vol 18 (1) ◽  
pp. 195-210
Author(s):  
E Roemer
Keyword(s):  
Working Group ◽  
Ring System ◽  
Minor Planets ◽  
The Sun ◽  
Ring Plane ◽  
Ring Systems ◽  
The Earth ◽  
Uranian Ring

An avalanche of discoveries pertaining to the satellite and ring systems of Jupiter and Saturn followed from the encounters of Pioneer 11 with Saturn, of Voyagers 1 and 2 with both Jupiter and Saturn, and from the passage of the Earth through the Saturn ring plane, all of which occurred during the triennium. The first comet discovery from a spacecraft also occurred during the same interval, a coronagraph experiment on the satellite P78-1 apparently catching a Kreutz sungrazer in the last hours before it impacted the Sun on 1979 August 30. Several successfully observed occultations of stars by the Uranian ring system, by minor planets, and possibly by satellites of Neptune and Pluto testify to efforts inspired by the Commission’s Working Group on Prediction of Occultations.

The rings of Uranus

1984 ◽  
Vol 75 ◽  
pp. 155-164 ◽  
Author(s):  
James L. Elliot
Keyword(s):  
Equatorial Plane ◽  
Kinematic Model ◽  
Theoretical Explanation ◽  
Ring System ◽  
Structural Details ◽  
Sharp Edges ◽  
Orbital Precession ◽  
Uranian Ring ◽  
Occultation Data ◽  
Geometric Albedo

ABSTRACTThe Uranian ring system consists of nine, narrow rings that have an average geometric albedo of 0.02. Since their discovery in 1977, the rings have been regularly observed with the technique of stellar occultations, which provides a spatial resolution of about 0.1 km in the positions of ring segments and about 4 km resolution in their structural details. The occultation data are well fitted by a kinematic model that describes the rings as ellipses, which are inclined to the equatorial plane of Uranus and precess due to harmonic terms in the Uranian potential field. The main characteristics of the Uranian ring system that need a confirmed theoretical explanation are: narrow rings, sharp edges, uniform orbital precession, origin of the eccentricities and inclinations, the structure of the e ring, the structure of the η ring and the origin of the ring system.

scholarly journals Thermal Emission from the Uranian Ring System

2019 ◽  
Vol 158 (1) ◽  
pp. 47 ◽  
Author(s):  
Edward M. Molter ◽  
Imke de Pater ◽  
Michael T. Roman ◽  
Leigh N. Fletcher
Keyword(s):  
Thermal Emission ◽  
Ring System ◽  
Uranian Ring

Near-infrared spectra of the uranian ring system

Icarus ◽  
2013 ◽  
Vol 226 (1) ◽  
pp. 1038-1044 ◽  
Author(s):  
Katherine de Kleer ◽  
Imke de Pater ◽  
Máté Ádámkovics ◽  
Heidi Hammel
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Ring System ◽  
Near Infrared Spectra ◽  
Uranian Ring

Current status of special planetary and lunar theories and ephemerides

1966 ◽  
Vol 25 ◽  
pp. 266-267
Author(s):  
R. L. Duncombe
Keyword(s):  
Observational Data ◽  
Current Status ◽  
Numerical Errors

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.

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