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Enceladus Jet Sources
ugordan
post Oct 10 2007, 05:20 PM
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New press release by the imaging team:

Cassini Pinpoints Hot Sources of Jets on Enceladus
October 10, 2007
(Source: Space Science Institute)

CICLOPS link to the release here.

One thing I was curious about tiger stripe naming - why didn't they switch "Baghdad" and "Cairo" so we have a nice A,B,C,D progression? I can only imagine it was done on purpose, but why?


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volcanopele
post Oct 10 2007, 05:27 PM
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Joe Spitale and Carolyn Porco have a paper in Nature, out tomorrow but online today, on the sources of Enceladus' South Polar jets entitled, "Association of the jets of Enceladus with the warmest regions on its south-polar fractures." As you can tell from the title, many of the jet sources are located near hotspots seen by CIRS, and nearly all are located along one of the tiger stripes in the south polar region. For those without access to the article, there is a press release located at http://saturn.jpl.nasa.gov/news/press-rele....cfm?newsID=780 . In addition, a map showing the hotspot and jet source locations can be found at http://photojournal.jpl.nasa.gov/catalog/PIA08385 . These are really intriguing results, and it would be interesting to see how these sources match up with those of the jets seen a couple of weeks ago. Are the sources variable? Are different parts of the stripes active at different times (as Terry Hurford suggests) or are they more constant and tied to thermal emission sites (as Spitale and Porco suggest)?

Enjoy!


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belleraphon1
post Dec 17 2007, 10:38 PM
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All..

I had seen this earlier in the AGU Abtracts but declined to post until we had some fuller reporting.
Unfortunately, this is all that has came forward so far.....


"Sodium issue clouds Enceladus"
http://news.bbc.co.uk/2/hi/science/nature/7145530.stm

quoting from this press release....

"A chemical analysis of Enceladus, led by University of Colorado planetary scientist Nick Schneider, failed to detect sodium, an element scientists say should be in a body of water that has had billions of years of contact with rock.

"If you have a long-lived ocean, it's going to have salt in it," said Dr Schneider, at the American Geophysical Union (AGU) meeting in San Francisco this week, "but that ocean, if it exists on Enceladus, isn't leaking out into space."

"Critics of the study accept his observations, but disagree with his conclusion; and it has led to some robust exchanges here at the AGU meeting this past week. "

March flyby through the plumes is gonna be really interesting....

Craig
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scalbers
post Dec 18 2007, 12:10 AM
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Interesting to see this sodium discussion continuing. There was also robust discussion after a similar talk by Nick Schneider at the August Outer Planet Satellites workshop.


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belleraphon1
post Dec 18 2007, 01:37 AM
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Very interesting indeed.

No Saknussemm Sea? (called this in the movie, not the book.... but it sounds better)
http://www.online-literature.com/verne/jou...enter_earth/30/


Cold Faithful - high temperature source for plumes
http://www.planetary.org/news/2007/0322_Ch...est_a_Soup.html
http://www.sciencenews.org/articles/20060506/bob9.asp
The process that converts NH3 to N2 and also creates CH4 through serpentization, involves reaction with a silicate core. Hard to see how the salts would be segregated out of the plumes.

Are the salts all in a non-ionized state and invisible? Can INMS detect salts?

Frigid Faithful - low temperature source for plumes
http://www.planetary.org/news/2006/1214_Ne..._Plumes_on.html
Are the organics at the plume sources captured from other sources in the Saturn system? Or primordial leftovers, not endogenic?

curiouser and curiouser....

Enceladus ain't easy..

Glorious....

Craig
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DFortes
post Dec 18 2007, 01:27 PM
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Yet another Enceladus plume model
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belleraphon1
post Dec 19 2007, 12:44 AM
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Dfortes... Clathrate Faithful? (Although Frigid Faithful also depends on clathrates, I believe)

Very interesting, sir.

I have to assume you are the autthor of this paper?

The paper mentions hydrothermal processing ..... as these xenoliths migrate upwards, would they drag "salts" up with them as well?

As much as I want that ocean to be there, the sodium issue makes me pause. What is really going on here, and what is the plume source? And what powers it?


Craig
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nprev
post Dec 19 2007, 12:59 AM
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Interesting indeed. Did the Keck observations search for any other elemental signatures other then Na, or was this even practical?


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DFortes
post Dec 19 2007, 07:17 AM
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QUOTE (belleraphon1 @ Dec 19 2007, 01:44 AM) *
Dfortes... Clathrate Faithful? (Although Frigid Faithful also depends on clathrates, I believe)

Very interesting, sir.

I have to assume you are the autthor of this paper?

The paper mentions hydrothermal processing ..... as these xenoliths migrate upwards, would they drag "salts" up with them as well?

As much as I want that ocean to be there, the sodium issue makes me pause. What is really going on here, and what is the plume source? And what powers it?


Craig



Thanks, yeah it's mine. I originally (in a moment of wholly uncharacteristic cynicism) called it tepid faithful. Settled on frothy faithful in the end. The difference with the existing clathrate model is that dissociation occurs in warm rising cryomagma whereas the Kieffer model is entirely dry.

As for the sodium - it is not obvious to me that this rules out the presence of an ocean. I would expect any salts to be carried in aqueous solution and be partitioned into hydrated crystalline phase on eruption, so you would not see the expected spectral signature. In the near IR these hydrated salts will appear similar to ice. Whether or not these salts would become coloured after radiation processing I do not know. Sputtering might yield a small flux of cations - depends on the salt; might be Na, Mg, NH4 etc...

Dom
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belleraphon1
post Dec 19 2007, 01:21 PM
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QUOTE (DFortes @ Dec 19 2007, 02:17 AM) *
Thanks, yeah it's mine. I originally (in a moment of wholly uncharacteristic cynicism) called it tepid faithful. Settled on frothy faithful in the end. The difference with the existing clathrate model is that dissociation occurs in warm rising cryomagma whereas the Kieffer model is entirely dry.

As for the sodium - it is not obvious to me that this rules out the presence of an ocean. I would expect any salts to be carried in aqueous solution and be partitioned into hydrated crystalline phase on eruption, so you would not see the expected spectral signature. In the near IR these hydrated salts will appear similar to ice. Whether or not these salts would become coloured after radiation processing I do not know. Sputtering might yield a small flux of cations - depends on the salt; might be Na, Mg, NH4 etc...

Dom


Frothy Faithful... I LIKE that.

Thanks for the clarification between the Frothy and Frigid models, Dom. And your take on the sodium issue. I feel a little more reassured regarding an ocean. smile.gif

UMSF is greatly enriched by having researchers and mission ops folks among it's members.

Thanks again.

Craig
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Guest_Zvezdichko_*
post Feb 8 2008, 07:17 PM
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http://saturn.jpl.nasa.gov/news/features/feature20080207.cfm - Enceladus plume model... scientists suggest an underground lake.
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ustrax
post Mar 6 2008, 04:27 PM
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March 12 flyby description available at Ciclops. smile.gif


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scalbers
post Mar 22 2008, 06:23 PM
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Here's a nice powerpoint I came across about Enceladus and its heating - by Tanya Harrison. The pros and cons of the liquid H2O vs clathrate hypotheses are summarized.

http://mgilmore.web.wesleyan.edu/wescourse...1/enceladus.ppt


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MahFL
post Jun 13 2008, 01:53 PM
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From http://ciclops.org/index.php
"And most exciting of all: the highest temperatures now measured are about 180 Kelvins, some 63 degrees Fahrenheit warmer than estimated from previous measurements. Though by no means a guarantee, these results make the possibility of liquid water close to the surface of the moon even more likely. Sacre bleu!..."

Water water everywhere !!!!!
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tasp
post Jun 13 2008, 03:26 PM
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Maybe . . . .

no, probably not.
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