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Faint Ring Thread, Saturn's D, E and G rings
alan
post May 10 2007, 02:45 PM
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This looks like a good opportunity to observe the d-ring:

http://space.jpl.nasa.gov/cgi-bin/wspace?t...=1&showsc=1

Any images planned at this time?
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bdunford
post Jun 1 2007, 07:45 PM
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What are we seeing in this image that was targeting the G-ring?

http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=112363

If you turn your monitor brightness up, a 'goblet' shape is visible. Is that a camera artifact? Or the shadow of the planet and rings? Or something else?


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Rob Pinnegar
post Jul 26 2007, 06:52 PM
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Just as a news note:

There's a recent D-Ring paper in Icarus -- the first major paper on the subject since 1996, as far as I know.

"Saturn's dynamic D ring", by Hedman et al., Icarus 188 (2007), 89-107.

I've only had a chance to skim it, but it contains some interesting material.
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ugordan
post Aug 18 2008, 12:10 PM
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Two long exposure images of the G ring:

http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=166193
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=166194

They show a streak right in the densest part of the ring that could be a solid object smeared by the long exposure. It's not in the direction of the stars and roughly follows the orbital motion of the ring (depends what point Cassini was exactly tracking so it makes it slightly sideways).

I know of denser clumps of icy particles isolated/theorized in the G ring, but has a more compact object (moonlet ?) ever been observed there?


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Floyd
post Aug 18 2008, 06:17 PM
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I agree that it looks like something very interesting. Tracks the ring perfectally.


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Floyd
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bdunford
post Aug 18 2008, 06:51 PM
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If confirmed, I vote they name the moonlet after you, Gordan. smile.gif


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ugordan
post Aug 18 2008, 06:59 PM
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LOL!


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ilbasso
post Aug 19 2008, 11:46 AM
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Any chance that it's the Millennium Falcon trying to hide amidst the debris?


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Jonathan Ward
Manning the LCC at http://www.apollolaunchcontrol.com
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jasedm
post Aug 19 2008, 12:47 PM
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Well spotted Gordan!
The fact that it appears in two separate frames increases the likelihood of it being a 'real' object rather than an artifact in the optics.
One of the frames cropped, enhanced and magnified:



Attached thumbnail(s)
Attached Image
 
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Ken90000
post Aug 19 2008, 06:05 PM
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Personally, I think it is awfully bright to be an undiscovered moon. It is brighter than the Op Nav shots of Pallene and Methone that we are used to seeing. Likewise, that is a lot of orbital motion for the relatively short exposure which looks to me to be a few second given the few stars included.

My vote is it is a clump of larger rocks that appear brighter at this phase angle.
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tedstryk
post Aug 23 2008, 03:13 PM
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During the ring plane crossing in the 1990s, Hubble spotted quite a few transient clumps in the rings. That may be what this is. It would be awesome if Cassini could get a closeup of one of them, although I realize how difficult that would be.


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Floyd
post Aug 23 2008, 04:26 PM
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Nice series of 10 G-Ring crossing images from August 22.



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Floyd
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Floyd
post Aug 24 2008, 01:23 AM
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Also two more pictures of the clump taken on August 22.


August 22 images:
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00119215.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00119214.jpg
August 15 images:
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00118601.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00118600.jpg

The pictures taken on the 22nd look exactly like those on the 15th, so clump or smeared object doesn't change much over a 7 day period.


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Floyd
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Floyd
post Aug 24 2008, 01:05 PM
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The team now has good orbital data on the G-Ring object(s) with the images 7 days apart. I would guess that these first two sets of images were taken to keep as much of the ring in focus as possible-but not worrying about smear along track. Over the next few orbits, they should be able to take images tracking the object(s), but smearing out more distant parts of ring. Cassini will be have 7 more revolutions in this 7-day orbit before the next Enceladus encounter.
I'm betting that it is a small moon. smile.gif



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Floyd
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Rob Pinnegar
post Aug 24 2008, 01:42 PM
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This is very interesting.

The two ends of the smeared ring "event" seem quite abrupt, similar to the background starlines, which suggests a discrete object rather than a "clump". But for a compact enough clump maybe this wouldn't be an issue -- and, as has already been pointed out, if it's a moonlet why haven't we seen it already?

Maybe we're looking at the formative stages of a transient clump? That would be great. (If true.)
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