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Posted by: SigurRosFan Sep 7 2005, 12:19 AM

http://spaceflightnow.com/news/n0509/06deepimpact/

The article shows a image with the impact site:

"This composite image was built up from scaling all images from Deep Impact to 5 meters/pixel, and aligning images to fixed points. Each image at closer range, replaced equivalent locations observed at a greater distance. The impact site has the highest resolution because images were acquired until about 4 sec from impact or a few meters from the surface. Arrows A and B point to large, smooth regions. The impact site is indicated by the third large arrow. Small arrows highlight a scarp that is bright due to illumination angle, which shows the smooth area to be elevated above the extremely rough terrain. The scale bar is 1 km and the two arrows above the nucleus point to the sun and the rotational axis of the nucleus. Celestial north is near the rotational pole.
Credit: NASA/JPL/UMd"

Posted by: Bob Shaw Sep 7 2005, 09:30 AM

And here's the image:

Posted by: djellison Sep 7 2005, 09:39 AM

I probbaly shouldnt do this...but...

This was a question asked at the end of Mike's talk to the BAA

http://www.unmannedspaceflight.com/doug_images/crater_size.mp3 (100kb)

Doug

Posted by: paxdan Sep 7 2005, 10:12 AM

Can someone please tell me if the angle of incidence is know for the impact. I have heard that it was much shallower than they intended, i.e., they were hoping for something at about 90 degrees but ended up with something closer to 25 degees.

Given that controlled hypervelocity impacts into comets are represented by a case study of one, please excuse my ignorance, but if there was a very shallow impact surely this would generate some interesting questions about the ejecta observed.

For example, perhaps a glancing impact did not bore to the same depth and if the dust layer was a few tens of meters thick, might a shallow impact angle account for the discrepancies between expectation of subsurface volatiles being ejected versus the very dusty ejecta seen, or is there an angle of incidence above/below which you invariably get an almost circular crater penetrating to the same depth. Given we know what the ejecta was and how it formed an initial plume, how much does this help us pin down crater morphologies, angle of incidence etc...

Unfortunately becasue of the failure to directly observe the crater we do not know what the morphology is. All the talk of seeing layers in the crater after impact, have been replaced with the same 'we expect it was 80-100 m in diameter' educated guesswork that was going on before the mission. I'm still waiting to see this processed picture showing the crater i've heard renewed rumours of.

That being said, we would all be dissapointed if a space mission didn't throw up more questions than answers, for what would there be left to discover

Edited for schpellink...

Posted by: SigurRosFan Sep 7 2005, 10:14 AM

Higher resolution image:

http://www.jpl.nasa.gov/images/deepimpact/2005-09-06/1118923Fig1browse.jpg (49 KB)

Posted by: tedstryk Sep 7 2005, 10:14 AM

I wish they had released a version without arrows.

Posted by: paxdan Sep 7 2005, 10:23 AM

If the whole eroding scarp theory of outgassing is correct.. i'm gonna do a Alfred Wegener and say it sure looks like that scarp could be witdrawing from the area which exposes the cratered site of impact... perhaps we are seeing the exposure of a different older unit under a from under fresher surface...

Edited to clarify: that is not to say we looking at plate techtonics just that if that scarp is eroding it looks to me like it is the same shape as the area from which it is pulling back from... see very crude attached annotated figure... e.g., scarp eroding in the directions of the white arrows from boundary indicated by orange line and arrows... same unit as scarp also indicate by blue line on the right of the image....

Posted by: Myran Sep 7 2005, 10:47 AM

I didnt think you ment plates paxdan, but that you talked about ice from some gases that have frozen out and now were melting again.

Now that might not have been what you ment, but my interpretation of what the smoother areas might be. And thats surprising, we sure would expect that on one comet with a highly elliptic orbit, but perhaps not this one.

Posted by: ljk4-1 Sep 30 2005, 04:15 PM

Paper: astro-ph/0509850
Date: Wed, 28 Sep 2005 16:24:38 GMT (62kb)

Title: SWAS observations of comet 9P/Tempel 1 and Deep Impact

Authors: Frank Bensch, Gary J. Melnick, David A. Neufeld, Martin Harwit,
Ronald L. Snell, Brian M. Patten

Categories: astro-ph

Comments: to appear in the proceedings of the IAU Symposium No. 231:
"Astrochemistry - Recent Successes and Current Callenges"

On 4 July 2005 at 1:52 UT the Deep Impact mission successfully completed its
goal to hit the nucleus of 9P/Tempel 1 with an impactor, forming a crater on
the nucleus and ejecting material into the coma of the comet.

The 370 kg impactor collided with the sunlit side of the nucleus with a relative velocity of 10.2 km/s. NASA's Submillimeter Wave Astronomy Satellite (SWAS) observed the 1(10)-1(01) ortho-water ground-state rotational transition in comet 9P/Tempel 1 before, during, and after the impact.

No excess emission from the impact was detected by SWAS. However, the water production rate of the comet showed large natural variations of more than a factor of three during the weeks before the impact.

\\ ( http://arXiv.org/abs/astro-ph/0509850 , 62kb)

Posted by: Ian R Oct 1 2005, 12:15 AM

Ask Ted, and ye shall receive!

http://antwrp.gsfc.nasa.gov/apod/image/0509/tempel1Res_deepimpact_f.jpg

Posted by: alan Oct 1 2005, 12:37 AM

The smooth patch on Temple1 has a dark teardrop shaped area with rays leading towards it edge. Could it be the source of a jet?

Posted by: ljk4-1 Oct 28 2005, 02:05 PM

Astrophysics, abstract
astro-ph/0505377

From: Edward M. Drobyshevski [view email]

Date (v1): Wed, 18 May 2005 14:02:44 GMT (369kb)
Date (revised v2): Fri, 3 Jun 2005 17:34:45 GMT (327kb)
Date (revised v3): Thu, 27 Oct 2005 13:11:39 GMT (260kb)

The Large-Scale Electrochemistry and Possible Consequences of Deep Impact Mission to Tempel 1

Authors: E.M.Drobyshevski, E.A.Kumzerova, A.A.Schmidt

Comments: 14 pages including 3 figures

Some consequences of hypervelocity impact onto the comet Tempel 1 nucleus are considered under assumption that SP comets are fragments of massive icy envelopes of Ganymede-like bodies saturated by products of ice electrolysis that underwent global explosions.

http://arxiv.org/abs/astro-ph/0505377