Orbits of shepherd satellites deduced from the structure of the rings of Uranus

@article{Murray1990OrbitsOS,
  title={Orbits of shepherd satellites deduced from the structure of the rings of Uranus},
  author={Carl D. Murray and Robert P. Thompson},
  journal={Nature},
  year={1990},
  volume={348},
  pages={499-502}
}
The sharp edges of the rings of Uranus require the presence of small satellites to halt radial spreading. There are several key locations in the ring system where satellites would be most effective at confining rings. Some of these are close to resonances with the moon Cordelia, and there is indirect evidence for the existence of at least two of these satellites. 
Uranus’s Hidden Narrow Rings
In addition to its suite of narrow dense rings, Uranus is surrounded by an extremely complex system of dusty rings that were most clearly seen by the Voyager spacecraft after it flew past the planet.
The Dynamics of Planetary Rings and Small Satellites
All the giant outer planets of the solar system possess ring systems, each with an accompanying retinue of small satellites. Although the ring systems of Jupiter, Saturn, Uranus and Neptune have
ARE THERE MOONLETS NEAR THE URANIAN α AND β RINGS?
The Voyager 2 Radio Science Subsystem occultations of the Uranian α and β rings exhibit quasi-periodic optical depth variations with radial wavelengths that vary with longitude. These patterns may be
Planetary ring dynamics
  • C. Murray
  • Physics, Geology
    Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences
  • 1994
The dynamics of planetary rings are reviewed in the light of data derived from the recent spacecraft missions to the outer planets. It is shown that although the ring systems of Jupiter, Saturn,
Weighing Uranus’ Moon Cressida with the η Ring
The η ring is one of the narrow rings of Uranus, consisting of a dense core that is 1–2 km wide and a diffuse outer sheet spanning about 40 km. Its dense core lies just exterior to the 3:2 Inner
Origins of the rings of Uranus and Neptune: 1. Statistics of satellite disruptions
Stochastic simulations of the collisional fragmentation of the small moons of Neptune and Uranus confirm the conclusions of Smith et al. [1986, 1989] that many of these moons cannot have survived
Evolution of planetary ringmoon systems
The last few decades have seen an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of these
Understanding Planetary Rings
The rings in the solar system and the mathematical and physical approaches to understanding them are described. The variety of ring phenomena revealed in recent years from space and earth-based
Dusty Rings and Circumplanetary Dust: Observations and Simple Physics
Each giant planet is encircled by planetary rings, usually composed of particles centimeters to meters in radius, but each system also contains regions where much smaller dust grains predominate.
...
...

References

SHOWING 1-10 OF 23 REFERENCES
Orbits of the ten small satellites of Uranus
Orbital elements are presented for the ten small satellites discovered by Voyager 2 at Uranus. These ten new satellites, whose provisional IAU designations are 1985UI and 1986UI through 1986U9, lie
Creation of the Uranus rings and dust bands
VOYAGER observations of the extended hydrogen exosphere of Uranus and of the σ Ring and its shepherds set an upper limit to the age of the σ Ring of 6 × 108 years. Unless we are seeing Uranus at a
Shepherding of the Uranian rings. I. Kinematics
We identify several orbital resonances involving the newly discovered satellites, 1986U7 and 1986U8, and the Uranian rings. The most important resonances in eccentric rings are known as eccentric
Shepherding of the Uranian Rings. II. Dynamics
We explore the dynamical significance of the orbital resonances, identified in Paper I (Porco and Goldreich 1987), involving the satellites 1986U7 and 1986U8, and the є, δ, and y rings. We
Existence of moonlets in Saturn's rings inferred from the optical depth profile
IT has been suggested1,2 that small satellites of diameter less than 50 km (moonlets) could exist within planetary rings, and could cause 'grooves' of low density in the adjacent ring material. Here
Wavy edges suggest moonlet in Encke's gap
Voyager images have revealed radial undulations of the inner and outer edges of the 325 km wide Encke gap in Saturn's A ring. These waves are present at some, but not all, longitudes. Their locations
The Dynamics of Planetary Rings
The discovery of ring systems around Uranus and Jupiter, and the Pioneer and Voyager spacecraft observations of Saturn, have shown that planetary rings are both more common and more complex than
...
...