The cause of Encke's division in Saturn's ring

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.

A review of radar observations of Saturn’s rings

10.1017/s0252921100100995 ◽

1984 ◽

Vol 75 ◽

pp. 49-55 ◽

Cited By ~ 1

Author(s):

Steven J . Ostro ◽

Gordon H. Pettengill

Keyword(s):

Ring System ◽

Radar Observations ◽

Jet Propulsion ◽

Tracking Station ◽

The Past ◽

Microwave Radar ◽

Radar Echoes ◽

Saturn’S Rings ◽

Saturn's Rings ◽

Arecibo Observatory

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.

Structure and dynamical processes in Saturn's rings

10.1017/s0252921100101447 ◽

1984 ◽

Vol 75 ◽

pp. 393-395

Author(s):

Richard J. Terrile

Keyword(s):

High Resolution ◽

Large Scale ◽

Large Scale Structure ◽

Ring Structure ◽

Ring System ◽

Scale Structure ◽

Dynamical Processes ◽

Saturn’S Rings ◽

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.

Origin and Evolution of Saturn’s Rings

Highlights of Astronomy ◽

10.1017/s153929960000544x ◽

1983 ◽

Vol 6 ◽

pp. 435-442

Author(s):

G.E. Morfill

Keyword(s):

Ring System ◽

Planetary Rings ◽

Subsequent Evolution ◽

Origin And Evolution ◽

Saturn’S Rings ◽

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.

A priority of space exploration: observation of Saturn's rings from a Saturn orbiter

10.1017/s0252921100101873 ◽

1984 ◽

Vol 75 ◽

pp. 739-742

Author(s):

André Brahic

Keyword(s):

Complex System ◽

Space Exploration ◽

Ring System ◽

Electromagnetic Properties ◽

Small Particles ◽

Saturn’S Rings ◽

A Priority ◽

Saturn's Rings ◽

Phase Angles

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.

Comments on collision mechanics in ring systems

10.1017/s0252921100101472 ◽

1984 ◽

Vol 75 ◽

pp. 407-422

Author(s):

William K. Hartmann

Keyword(s):

Asteroid Belt ◽

Surface Erosion ◽

Surface Layers ◽

Ring Systems ◽

Eclipse Observations ◽

Saturn’S Rings ◽

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.

Voyager UVS observations of stellar occultations by the rings of Saturn

10.1017/s0252921100101265 ◽

1984 ◽

Vol 75 ◽

pp. 265-277

Author(s):

J.B. Holbelg ◽

W.T. Forrester

Keyword(s):

Optical Depth ◽

Distance Scale ◽

Density Waves ◽

Ring Density ◽

Stellar Occultations ◽

Saturn’S Rings ◽

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.

Comparisons of CODE and CNES/CLS GPS satellite bias products and applications in Sentinel-3 satellite precise orbit determination

GPS Solutions ◽

10.1007/s10291-021-01164-5 ◽

2021 ◽

Vol 25 (4) ◽

Author(s):

Bingbing Duan ◽

Urs Hugentobler

Keyword(s):

Linear Combination ◽

Orbit Determination ◽

Fractional Part ◽

Precise Orbit Determination ◽

Satellite Orbit ◽

Satellite Orbits ◽

Satellite Clock ◽

Analysis Center ◽

Wide Lane ◽

Total Difference

AbstractTo resolve undifferenced GNSS phase ambiguities, dedicated satellite products are needed, such as satellite orbits, clock offsets and biases. The International GNSS Service CNES/CLS analysis center provides satellite (HMW) Hatch-Melbourne-Wübbena bias and dedicated satellite clock products (including satellite phase bias), while the CODE analysis center provides satellite OSB (observable-specific-bias) and integer clock products. The CNES/CLS GPS satellite HMW bias products are determined by the Hatch-Melbourne-Wübbena (HMW) linear combination and aggregate both code (C1W, C2W) and phase (L1W, L2W) biases. By forming the HMW linear combination of CODE OSB corrections on the same signals, we compare CODE satellite HMW biases to those from CNES/CLS. The fractional part of GPS satellite HMW biases from both analysis centers are very close to each other, with a mean Root-Mean-Square (RMS) of differences of 0.01 wide-lane cycles. A direct comparison of satellite narrow-lane biases is not easily possible since satellite narrow-lane biases are correlated with satellite orbit and clock products, as well as with integer wide-lane ambiguities. Moreover, CNES/CLS provides no satellite narrow-lane biases but incorporates them into satellite clock offsets. Therefore, we compute differences of GPS satellite orbits, clock offsets, integer wide-lane ambiguities and narrow-lane biases (only for CODE products) between CODE and CNES/CLS products. The total difference of these terms for each satellite represents the difference of the narrow-lane bias by subtracting certain integer narrow-lane cycles. We call this total difference “narrow-lane” bias difference. We find that 3% of the narrow-lane biases from these two analysis centers during the experimental time period have differences larger than 0.05 narrow-lane cycles. In fact, this is mainly caused by one Block IIA satellite since satellite clock offsets of the IIA satellite cannot be well determined during eclipsing seasons. To show the application of both types of GPS products, we apply them for Sentinel-3 satellite orbit determination. The wide-lane fixing rates using both products are more than 98%, while the narrow-lane fixing rates are more than 95%. Ambiguity-fixed Sentinel-3 satellite orbits show clear improvement over float solutions. RMS of 6-h orbit overlaps improves by about a factor of two. Also, we observe similar improvements by comparing our Sentinel-3 orbit solutions to the external combined products. Standard deviation value of Satellite Laser Ranging residuals is reduced by more than 10% for Sentinel-3A and more than 15% for Sentinel-3B satellite by fixing ambiguities to integer values.