Dione! Options

[tedstryk]

Check out the new multispectral Dione series! Here is one of the frames:



Quite a lot of cracks!

[JRehling]

Check out the new multispectral Dione series!  Here is one of the frames:

Quite a lot of cracks!

Wow, I'll say. Color me surprised. I thought we might see the cracks localized, but instead it looks like their prevalence ranges from some to lots.

Also, note the huge, eroded impact basin near top.

The prevalence of the cracks means more than just an interesting thing about Dione. It provides stratigraphic evidence helpful to coming up with a relative age timeline that in turn provides a relative impact density history for the whole Saturn system. Good find! Of course, we can expect more cracks elsewhere in the Saturn system, and I daresay with so many moons that must have been geologically dead for a long while, we might end up with a surprisingly constrained *absolute* timeline -- that would be something!

[tedstryk]

Wow, I'll say. Color me surprised. I thought we might see the cracks localized, but instead it looks like their prevalence ranges from some to lots.

  Also, note the huge, eroded impact basin near top.

  The prevalence of the cracks means more than just an interesting thing about Dione. It provides stratigraphic evidence helpful to coming up with a relative age timeline that in turn provides a relative impact density history for the whole Saturn system. Good find! Of course, we can expect more cracks elsewhere in the Saturn system, and I daresay with so many moons that must have been geologically dead for a long while, we might end up with a surprisingly constrained *absolute* timeline -- that would be something!

The large craters near the center towards the terminator seem quite Enceladus-like, although this could be superficial - perhaps this is similar to the ancient part of Enceladus.

[Gsnorgathon]

I'm intrigued by that mountain on the limb at 11 o'clock. Central peak? Tectonic? And the cracks on the terminator are... what's the word? Enceladusesque?

[Guest_Sunspot_*]

Where did that picture come from? The RAW website is still broken for me.

EDIT: never mind, found it now.

[Decepticon]

I don't think that Huge crater has been seen yet!


Another amazing discovery!

[Phil Stooke]

Here is the giant basin in its true discovery image! - from Voyager.

It looks like the mountain on the limb is either a central peak or a high point on the common rim of two adjacent craters.

The basin was described in this reference:

http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1553.pdf

(see Figure 6).

Phil

[Decepticon]

^ Thanks for that the info Phil. So they kinda knew about it.


Also the shading on dione reminds me of Iaptues but on a lesser scale.

[dilo]

I made this mosaic from best two pictures; it containing also small enhanced false color image (from IR+G+UV filters):

Note stronger Here also a stereo image (cross-eyed):

[Guest_Myran_*]

Gsnorgathon wrote:

I'm intrigued by that mountain on the limb at 11 o'clock. Central peak?

Yes it is a central peak imagined by Voyager, as pointed out by Phil Stooke here.



Image PIA01366 by Voyager 1 on Nov. 12, 1980 from about 240,000 kilometers

[Phil Stooke]

The picture I posted earlier (link at bottom of reply 7) shows the big basin at the bottom, and a crater with a central peak at about the 5:00 position on the disk which must be the mountain on the limb in the new images. But that crater and peak are not the same as the features at the top of the picture in the new post just above.

Phil

[Guest_Myran_*]

Yes I stand corrected Phil, the central peak crater we did see from the side have a basin on the side which are missing on the image I brought here, my post was made at a very late hour so had too sleepy eyes I guess.

[ilbasso]

The central crater peaks on Dione's biggest craters (also on Tethys's) appear to be much larger, especially in height, relative to their parent craters than do central peaks on our Moon or Mars. Is this because of the material of which Dione is made, or because of its lower gravity?

[volcanopele]

The mountain is located at ~35S, ~105W so that crater might fit the bill. It appears to be the closest to that position.

[Phil Stooke]

The new Dione observations have been added to Steve Albers' excellent global mosaic at:

http://laps.fsl.noaa.gov/albers/sos/sos.html

And here, in another example of the polar projection method, I have cropped the bottom half of his map (in the spirit of open source image processing we are all enjoying... hope that's OK, Steve!) and used Photoshop's filter>distort>polar coordinates method to make a map of the southern hemisphere centered on the pole. This is what a cartographer would call an azimuthal equidistant projection (and the spherize tool could turn it into an equal area projection).

See the big basin... above it, across the data gap, we see the best Voyager image, and a group of ridges and crater chains long recognized in that area turn out to be radial to the basin. An ejecta lobe and basin secondaries, most likely.





Phil