Cassini at the DPS conference Options

[volcanopele]

The DPS conference in Pasadena is now in full swing (and I am not there). News and press releases are slowly trickling out of that conference, from New Scientist which reported on an Enceladus theory relating cosmic rays and Enceladus' jets and warm south polar region, to public releases at the Cassini JPL site, to glogger Brad Thomson reporting on the conference for the Planetary Society. So I thought I would create a thread just for Cassini news from this conference.

Enceladus
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There is already a thread regarding the Cooper et al. theory relating cosmic rays and the jets, so I won't touch on that here. Brad Thomson went to a few of the Enceladus talks and had a few interesting things to report. First, the ISS team is now moving away from the idea that the thrust faulting seen along the south polar terrain margin as well as the overall global tectonic pattern suggests that Enceladus experienced a flattening of its polar axis (due to an increasing in its rotation rate for example), and moving more toward a regional tectonism explaination. Again, any theory regarding the south polar terrain not only has to explain the appearance of that area, but also the tectonic pattern seen in other regions as well. Perhaps Nimmo and Pappalardo's diapir theory would work best here. The ISS team also reported on the leading hemisphere terrain. Only the western margin of this terrain has been observed at resolutions better than 1 km/pixel (that will change next year, IIRC), but what has been seen is reminiscent of the south polar region, with its criss-crossing network of ridges and troughs. Another example of a "south polar-like relic terrain" is south of Diyar and Sarandib Planitiae.

Brad also reported on talks given by John Spencer, Andy Ingersoll, and Feng Tian. John Spencer gave a plenary talk on the current state of Enceladus science on Monday. One interesting tidbit was that one of the Voyagers (I presume 2 since it came much closer to Enceladus) could have observed the tiger stripe sulci had it not been for an error that prevented the acquitition of high-resolutions of Enceladus. Would be curious to know the details on these observations (Phil?). Ingersoll examined the dynamics of the plumes and showed that some of the geysers point in directions different from normal to the surface (which of course complicates my vent location idents). Not sure about the continuous source comment. Maybe this has to do with CDA's need for a moon-wide source of dust in addition to the south polar source... Feng Tian's work on ejection velocities seem to further rule out sublimation as a plume mechanism.

Saturn
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VIMS has released an image, String of Pearls, which shows a pattern of cloud clearings in Saturn's northern hemisphere. These clearings maybe related to a large planetary wave at that latitude.

[Phil Stooke]

The Voyager problem that prevented observations of the tiger stripes was the infamous scan platform jamming - it happened at the time of the most target-rich part of the fly-by, when rapid slews were needed to observe everything. It caused the tragic loss of high resolution mosaics of the south pole of Enceladus and much of Tethys, as well as other observations. Superhuman efforts made the instruments operational in time for the distant Phoebe flyby a week or so later.

Phil

[volcanopele]

Faint Rings Fun
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The are two press releases dealing with talks by Matt Hedman on faint rings in the Saturnian system. The first, Saturn's rings show evidence of a modern-day collision, discusses analysis of the changing structure of the outer D-ring. Changes in the spacing of ringlets and the structure of these ringlets suggest that a collision occured between the D-ring and an outside meteor sometime in the mid-1980s. In the other release, analysis of high-phase images from last month indicate the presence of faint diffuse rings in the Cassini Division as well as in the orbits of Janus, Epimetheus, and Pallene.

A number of images accompany this release, including a mosaic of Saturn when the sun was behind it last month: http://photojournal.jpl.nasa.gov/catalog/PIA08329

[paxdan]

zOMFG!

[helvick]

Yeah - that is a very purdy picture indeed.

[nprev]

<clink>worthy!

[dilo]

zOMFG!

stunning!!!!!!!!!!!

[Borek]

A number of images accompany this release, including a mosaic of Saturn when the sun was behind it last month: http://photojournal.jpl.nasa.gov/catalog/PIA08329

Volcanopele, don't you know whether the released image is considerably downsampled? If yes, is there any chance of getting the full resolution thing?

Borek

[ugordan]

That is the full resolution thing. A number of the wide-angle frames were binned 2x2 onboard so there's nothing to be done there. The mosaic is still some 4000 pixels wide. I recommend getting the product directly from CICLOPS, they also provide PNG versions which are significantly smaller than TIFFs on Photojournal, while retaining losslessness.

[Borek]

That is the full resolution thing. A number of the wide-angle frames were binned 2x2 onboard so there's nothing to be done there. The mosaic is still some 4000 pixels wide.

I have asked because the big approach pan was some 8000px wide. But I understand, those were narrow-angle frames stitched together. Never mind, it's big enough

Borek

[SigurRosFan]

Here's my first star map version ...

Still i'm searching for Dione, Mimas and Mars.

Attached thumbnail(s)

 

[ugordan]

I don't know how meaningful it is to locate stars in a large mosaic such as this because there are too many individual footprints taken over some 3 hours that star positions will be pretty distorted during that time. Some stars might appear twice, while others not even once. There's too much parallax between footprints on account of slow readout times of the ISS cameras.

As an extreme example, I think Enceladus shows up twice in the mosaic, the other occurence being slightly to the right of your labeled version.

[ngunn]

An abstract and some interesting Bruce Moomaw comments here:
http://tech.groups.yahoo.com/group/jupiter_list/message/7515

[Rob Pinnegar]

That Saturnian panorama is pretty impressive. When I first saw the thumbnail version, I thought it was computer-generated artwork (similar to the Solar System Simulator, but with a bit more work). It took me a couple of seconds to realize that it was composed of processed real images.

[JRehling]

Here's my first star map version ...

Still i'm searching for Dione, Mimas and Mars.

One of the first things that surprised me was the near-moonlessness of this mosaic, but if you think about it, this is a very unfavorable phase angle for viewing an airless world.