Rev 141 - Nov 20-Dec 10, 2010 - Hyperion and Enceladus E12 |
Rev 141 - Nov 20-Dec 10, 2010 - Hyperion and Enceladus E12 |
Nov 22 2010, 02:34 PM
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#1
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Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
The latest article has been up a few days, and goodies include a doppler-tracking pass over Enceladus' northern hemisphere, a search for Rhea co-orbitals, and the first reasonable-range imaging of Hyperion for five years.
The article doesn't state whether a different hemisphere will be on view than that imaged during the targeted flyby in '05, but I suppose it would be very unlucky if this was the case. Images from the Hyperion encounter should be comparable to this: |
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Nov 22 2010, 03:42 PM
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#2
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Member Group: Members Posts: 540 Joined: 17-November 05 From: Oklahoma Member No.: 557 |
The rotation of Hyperion is chaotic, so it may not be possible to predict how it will be oriented very far in advance.
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Nov 29 2010, 01:17 AM
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#3
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Senior Member Group: Members Posts: 1414 Joined: 26-July 08 Member No.: 4270 |
-------------------- -- Hungry4info (Sirius_Alpha)
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Nov 29 2010, 01:21 AM
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#4
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Thank you, Hungry. Always good to see new views of our favorite celestial sponge!
Speaking of new views, has Hyperion's spin state been decisively resolved yet? I remember some buzz a few years back that it may be chaotic, but have heard nothing further for quite some time now. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Nov 29 2010, 01:36 AM
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#5
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Senior Member Group: Members Posts: 1414 Joined: 26-July 08 Member No.: 4270 |
Any time .
Hyperion's rotation axis was found to be chaotic from ground-based photometry after the Voyager encounters. Something to do with Titan being nearby? -------------------- -- Hungry4info (Sirius_Alpha)
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Nov 29 2010, 01:45 AM
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#6
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Yeah, it does get pretty close to The Big Guy, and that'd do it!
So, Cassini planners aren't completely sure what they're going to see during each of these encounters. Interesting. I wonder if there's any attempt to see if the spin-axis precession might be "stochastic" instead of straight-up chaotic (if you know what I mean) given that we can now resolve & record the relative positions of small-scale surface features during these encounters. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Nov 29 2010, 01:48 AM
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#7
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Senior Member Group: Members Posts: 1414 Joined: 26-July 08 Member No.: 4270 |
I was wondering the same thing and did some digging earlier and came across this paper, which seemed to rule that out.
The chaotic rotation of Hyperion QUOTE As tidal dissipation drives Hyperion's spin toward a nearly synchronous value, Hyperion necessarily enters the large chaotic zone. At this point Hyperion becomes attitude unstable and begins to tumble. Capture from the chaotic state into the synchronous or ½ state is impossible since they are also attitude unstable. The 3/2 state does not exist. Capture into the stable 2 state is possible, but improbable. It is expected that Hyperion will be found tumbling chaotically.
-------------------- -- Hungry4info (Sirius_Alpha)
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Nov 29 2010, 02:20 AM
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#8
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Solar System Cartographer Group: Members Posts: 10127 Joined: 5-April 05 From: Canada Member No.: 227 |
Hyperion's rotation has also been modelled as a slow long axis rotation with large precession, like the nucleus of Halley's comet and asteroid Toutatis:
Hyperion: Rotation, Shape, and Geology from Voyager Images Icarus, Volume 117, Issue 1, September 1995, Pages 128-148 P. C. Thomas, G. J. Black and P. D. Nicholson This would be complex but predictable, not chaotic. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Nov 29 2010, 03:06 AM
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#9
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Glad to see Cassini back at work. These images of Hyperion are phenomenal!
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Nov 29 2010, 06:52 AM
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#10
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Lord Of The Uranian Rings Group: Members Posts: 798 Joined: 18-July 05 From: Plymouth, UK Member No.: 437 |
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Nov 29 2010, 08:49 AM
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#11
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Member Group: Members Posts: 890 Joined: 18-November 08 Member No.: 4489 |
it is looking like i am going to need to add some new images to my map of Hyperion
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Nov 29 2010, 03:10 PM
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#12
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Member Group: Members Posts: 696 Joined: 3-December 04 From: Boulder, Colorado, USA Member No.: 117 |
...This would be complex but predictable, not chaotic. The latest analysis of Hyperion's rotation was presented at the 2010 DPS meeting in October. The precession of the spin axis is not behaving as expected, perhaps due to internal inhomogeneities. So we still don't have a good rotational model for Hyperion. And to nit-pick, there isn't a clear distinction between "predictable" and "chaotic" - "chaotic" behavior is always predictable in theory, given perfect knowledge of initial conditions- it's just that tiny changes in initial conditions translate to large variations in future behavior. [edit] I should add that it's my understanding that for Hyperion the rate at which its rotation would diverge from predictions (if we had a good enough understanding of its current behavior to make predictions) is fairly slow (many months?), so while it's truly chaotic it's less chaotic than many other systems, such as the Earth's weather. John |
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Nov 29 2010, 08:36 PM
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#13
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Solar System Cartographer Group: Members Posts: 10127 Joined: 5-April 05 From: Canada Member No.: 227 |
Thanks - I hadn't seen that abstract.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Nov 29 2010, 08:38 PM
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#14
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
Looks like the remaining Hyperion images have been dumped onto the raw pages.
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Nov 29 2010, 09:14 PM
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#15
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Member Group: Members Posts: 555 Joined: 27-September 10 Member No.: 5458 |
Did a little bit of processing on some of the new data and came up with this:
This is a false color image using the IR1, GRN and UV3 filters. Also, it looks like a few images of Titan were actually snapped. A good range of filters were used including Red, GRN, BL1. After a little processing it produced this: I'm sure someone can do better than this with the data. These were done in a really short time (less than 20m). It looks like a great flyby movie could be done of Hyperion as well. -------------------- |
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