First Sharp Look at a Uranian Ring

Science News ◽  
1985 ◽  
Vol 128 (24) ◽  
pp. 373
Author(s):  
J. Eberhart
Keyword(s):  
Uranian Ring

Uranian ring orbits from earth-based and Voyager occultation observations

Icarus ◽  
1988 ◽  
Vol 73 (2) ◽  
pp. 349-378 ◽  
Author(s):  
Richard G. French ◽  
J.L. Elliot ◽  
Linda M. French ◽  
Julie A. Kangas ◽  
Karen J. Meech ◽  
...  
Keyword(s):  
Uranian Ring

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

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.

Uranian ring photometry: Results from Voyager 2

1987 ◽  
Vol 92 (A13) ◽  
pp. 14969 ◽  
Author(s):  
Maureen E. Ockert ◽  
Jeffrey N. Cuzzi ◽  
Carolyn C. Porco ◽  
Torrence V. Johnson
Keyword(s):  
Voyager 2 ◽  
Uranian Ring

Uranian ring dynamics: An analysis of multimode motions

Icarus ◽  
1989 ◽  
Vol 82 (2) ◽  
pp. 281-287 ◽  
Author(s):  
Pierre-Yves Longaretti
Keyword(s):  
Ring Dynamics ◽  
Uranian Ring

Voyager photopolarimeter observations of Uranian ring occultations

Icarus ◽  
1990 ◽  
Vol 83 (1) ◽  
pp. 102-125 ◽  
Author(s):  
Joshua E. Colwell ◽  
L.J. Horn ◽  
A.L. Lane ◽  
L.W. Esposito ◽  
P.A. Yanamandra-Fisher ◽  
...  
Keyword(s):  
Uranian Ring

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.

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