[X] My Assistant

[alan]

Six days to go until Enceladus flyby ( E2? ) at 175 km

[remcook]

news release:

http://saturn.jpl.nasa.gov/news/press-rele....cfm?newsID=592

very interesting indeed! Looks more and more like Europa, only active!

[dilo]

The magnetometer instrument confirmed an atmosphere at Enceladus during the July 14 flyby.  Data from this flyby and modeling work of previous data shows that the atmosphere is concentrated over the south polar region and is much more rarified over the rest of the surface.

http://www.unmannedspaceflight.com/index.p...ype=post&id=339
...something like this, Jason?
See http://www.unmannedspaceflight.com/index.p...findpost&p=5657

[volcanopele]

Sorry for the double post, didn't realize I was posting in the wrong thread:

nope, still an image artifact. If it were real, then when viewed from the same geometry, here are plumes over Mimas, Rhea, Tethys, and Titan over the same area of the crescent.

However, I can't deny we haven't gone back and taken another look at it. but mostly likely the activity we are seeing is do to evaporation or outgassing rather than a full fledged plume.

[David]

And now for the punch-line: CIRS found a hot spot near Enceladus' south pole:

http://photojournal.jpl.nasa.gov/catalog/PIA06432

Fantastic stuff! Too bad it's still 150 below freezing. I wonder how much hotter it might get inside Enceladus?

[Decepticon]

Enceladus looks more like Ganymede instead of Europa.

[scalbers]

How neat that this is the punchline to the evidence building up over months and even decades. Perhaps 6-12 months ago, the Y shaped features looked at low resolution like some sort of amorphous petals of a giant flower ringing the south pole. Even then something strange was being foreshadowed and how fun it has been to see the resolution gradually increase since then.

Yesterday (July 29) there was a CICLOPS release of the tiger scratches in enhanced color close up. Overlain are 10 squares showing the CIRS temperature measurement pixels. It actually can pinpoint the tiger scratches as the heat source.

[dilo]

Sorry for my insistence, Jason. Can you kindly pinpoint an image showing similar artifact on Mimas, Rhea, Tethys, and Titan? thkx

[JRehling]

And now for the punch-line: CIRS found a hot spot near Enceladus' south pole:

http://photojournal.jpl.nasa.gov/catalog/PIA06432

I'll point out: Those nifty temperature profiles across a tiger scratch showing higher temps in the scratch area are of pretty low resolution, so their reading of a higher temperature may be quantitatively averaging "normal" surface units with a smaller, very-warm lineated feature. The actual high temperature -- who knows? Something near 0C would be exciting. I don't know if the remaining Enceladus flyby of the regular mission will inspect this or not -- given the geometry, I give it an odds-on "I doubt it".

Next we have to see if the north pole area also has a warm spot of any kind.

[DEChengst]

I'll point out: Those nifty temperature profiles across a tiger scratch showing higher temps in the scratch area are of pretty low resolution, so their reading of a higher temperature may be quantitatively averaging "normal" surface units with a smaller, very-warm lineated feature. The actual high temperature -- who knows? Something near 0C would be exciting.

Even a much lower temperature can be exciting. An ammonia-water eutectic mixture is liquid at 176 Kelvin, so there might very well be active cryo volcanos on Enceladus.

[tty]

I wonder could those "tiger scratches" be something analogous to mid-ocean ridges where "lava" from below intrudes and pushes "lithospheric" plates apart?

tty

[volcanopele]

Sorry for my insistence, Jason. Can you kindly pinpoint an image showing similar artifact on Mimas, Rhea, Tethys, and Titan? thkx

I'll have to check with the person who did the analysis on the problem.

[volcanopele]

I'll point out: Those nifty temperature profiles across a tiger scratch showing higher temps in the scratch area are of pretty low resolution, so their reading of a higher temperature may be quantitatively averaging "normal" surface units with a smaller, very-warm lineated feature. The actual high temperature -- who knows? Something near 0C would be exciting. I don't know if the remaining Enceladus flyby of the regular mission will inspect this or not -- given the geometry, I give it an odds-on "I doubt it".

Next we have to see if the north pole area also has a warm spot of any kind.

As DEChengst pointed out, you don't need 0C for liquid water thanks to ammonia, assuming it is there. In terms of pixels, the CIRS team determined that in the 91K box, color temperatures are consistent with a background temperature of 85K or so, with 1% at 140 K. 1% of a 6x6 km box is .36 km2, consistent with a box-shaped area of about 19.5x19.5 m.

The other thing I was going to say, the north polar region is deader than a doornail (or Mimas, same thing). 38K or so.

[tedstryk]

The other thing I was going to say, the north polar region is deader than a doornail (or Mimas, same thing).  38K or so.

Hardly suprising....it looks old and battered. I have marked it here with an arrow.

[tty]

As DEChengst pointed out, you don't need 0C for liquid water thanks to ammonia, assuming it is there.  In terms of pixels, the CIRS team determined that in the 91K box, color temperatures are consistent with a background temperature of 85K or so, with 1% at 140 K.  1% of a 6x6 km box is .36 km2, consistent with a box-shaped area of about 19.5x19.5 m.

Actually 0.36 km2 is 600 x 600 meters, or since we are talking about linear features 6000 x 60 meters.

tty

[volcanopele]

grrr....true, very true. It was a Sunday morning..I'm never awake on a sunday morning.