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TOPIC: Saturn's rings


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RE: Saturn's rings
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Shadow from the Dark Side
Image taken by the Cassini spacecraft showing Saturn's A ring on the left, Cassini Division in the middle and dense outer B ring on the right.
Credit NASA

View video (742 Kb)

The shadow of Saturn's moon Tethys seems to disappear as it crosses the planet's rings, demonstrating variations in the density of particles across the rings.
These images, which were combined to create a mosaic and a movie, show Saturn's A ring on the left, Cassini Division in the middle and dense outer B ring on the right. The Cassini spacecraft looks toward the unilluminated side of the rings in these frames from about 49 degrees above the ringplane.

Source


-- Edited by Blobrana on Monday 22nd of June 2009 06:10:37 PM

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Tiny moons embedded in Saturn's ring system create gravitational speed bumps that redirect the flow of particles, new findings from the Cassini spacecraft show.
Taking advantage of a very low sun angle relative to the planet's rings, Cassini scientists found long shadows in a ring gap created by the eight-kilometre-wide Saturn moon Dephnis, which orbits in Saturn's outer A ring.

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Ed ~ The moon is called Daphnis

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Saturn's F ring
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Title: Appearance of Saturn's F ring azimuthal channels for the anti-alignment configuration between the ring and Prometheus
Authors: Carlos E. Chavez

In this article we explore the aspect of the F ring with respect to the anti-alignment configuration between the ring and Prometheus. We focus our attention on the shape of the F ring's azimuthal channels which were first reported by Porco et al. (2005) and numerically explored by Murray et al. (2005), who found excellent agreement between Cassini's ISS reprojected images and their numerical model via a direct comparison. We find that for anti-alignment the channels are wider and go deeper inside the ring material.
From our numerical model we find a new feature, an island in the middle of the channel. This island is made up of the particles that have been perturbed the most by Prometheus and only appears when this satellite is close to apoapsis. In addition, plots of the anti-alignment configuration for different orbital stages of Prometheus are obtained and discussed here.

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RE: Saturn's rings
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Saturn's comparatively paper-thin rings are tilted edge on to Earth every 15 years. Because the orbits of Saturn's major satellites are in the ring plane, too, this alignment gives astronomers a rare opportunity to capture a truly spectacular parade of celestial bodies crossing the face of Saturn. Leading the parade is Saturn's giant moon Titan - larger than the planet Mercury.

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NASA's Cassini spacecraft has found within Saturn's G ring an embedded moonlet that appears as a faint, moving pinprick of light. Scientists believe it is a main source of the G ring and its single ring arc.
Cassini imaging scientists analysing images acquired over the course of about 600 days found the tiny moonlet, half a kilometre across, embedded within a partial ring, or ring arc, previously found by Cassini in Saturn's tenuous G ring.
The finding is being announced today in an International Astronomical Union circular.

pia11148-browse.jpg

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Nine New Ring Gap Names
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The IAU has approved nine new names for Saturn's ring system gaps: Bond Gap, Dawes Gap, Herschel Gap, Russell Gap, Jeffreys Gap, Kuiper Gap, Laplace Gap, Bessel Gap, and Barnard Gap.

Rings of Saturn Name Distance
from planet's center (km)
Width (km)

Rings and gaps.

D 67,000 - 74,490 7,500
C 74,490 - 91,980 17,500
Colombo Gap 77,800 100
Maxwell Gap 87,500 270
Bond Gap 88,690-88,720 30
Dawes Gap 90,200-90,220 20
B 91,980 - 117,500 25,500
Cassini Division 117,500 - 122,050 4,700
Huygens Gap 117,680 285-440
Herschel Gap 118,183-118,285 102
Russell Gap 118,597-118,630 33
Jeffreys Gap 118,931-118,969 38
Kuiper Gap 119,403-119,406 3
Laplace Gap 119,848-120,086 238
Bessel Gap 120,236-120,246 10
Barnard Gap 120,305-120,318 13
A 122,050 - 136,770 14,600
Encke Gap 133,570 325
Keeler Gap 136,530 35
Roche Division 136,770-139,380 2600
F 140,224 30-500
G 166,000 - 174,000 8,000
E 180,000 - 480,000 300,000


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RE: Saturn's rings
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N00128147.jpg
Expand (33kb, 1024 x 1024)
Credit: NASA/JPL/Space Science Institute

This image of Saturns rings was taken on January 14, 2009 by the Cassini space probe when it was approximately 537,142 kilometres away.
The image was taken using the CL1 and CL2 filters.

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Saturn's F ring
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Title: Physical collisions of moonlets and clumps with the Saturn's F-ring core
Authors: Sebastien Charnoz

Since 2004, observations of Saturn's F ring have revealed that the ring's core is surrounded by structures with radial scales of hundreds of kilometres, called "spirals" and "jets". Gravitational scattering by nearby moons was suggested as a potential production mechanism; however, it remained doubtful because a population of Prometheus-mass moons is needed and, obviously, such a population does not exist in the F ring region. We investigate here another mechanism: dissipative physical collisions of kilometre-size moonlets (or clumps) with the F-ring core. We show that it is a viable and efficient mechanism for producing spirals and jets, provided that massive moonlets are embedded in the F-ring core and that they are impacted by loose clumps orbiting in the F ring region, which could be consistent with recent data from ISS, VIMS and UVIS. We show also that coefficients of restitution as low as ~0.1 are needed to reproduce the radial extent of spirals and jets, suggesting that collisions are very dissipative in the F ring region. In conclusion, spirals and jets would be the direct manifestation the ongoing collisional activity of the F ring region.

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RE: Saturn's rings
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All year long, the rings of Saturn have been tilting toward Earth and now they are almost perfectly edge-on. The opening angle is a paper-thin 0.8. Viewed from the side, the normally wide and bright rings have become a shadowy line bisecting Saturn's two hemispheres--a scene of rare beauty.

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