I think it's most likely that the dark stuff is hydrocarbon gunk cooked up from the ambient methane by the high temperatures of the impact. The dark stuff in the diffuse halo may even form in place, from the high temperatures generated when the ejecta slams back into the upper atmosphere- heat from that mechanism was what produced the bright near-IR flashes seen in the SL9 impacts.

John

Since these impacts are apparently fairly frequent (since we have observed two in a short time) and the "gunk" produced should be fairly stable in the low temperatures prevailing in the upper atmosphere one wonders how much "gunk" accumulates and to what extent it contributes to Jupiter's colourful atmosphere.
I would expect that the molecules will ultimately sink deep enough into the atmosphere for the heat to break them up into simple molecules again, but that should be a slow process.

The new images from Hubble are going to be incredible -- does anyone have an idea of how frequently they will be updating?

The impact feature is easily visible on small telescopes.
Here's an image I got last night:
Click to view attachment

I didn't expect it to be that detailed, so it's really worth to observe if you can, even if just visually.

Given that the frequency of large impacts may be higher than we have thought, Junocam might end up being a very useful asset indeed!
P

The status of the HST program (number 12003, PI Heidi Hammel) may be found here. It shows an initial 2-orbit allocation later increased to 5. Two orbits were used for a series of 18 exposures on 23 July, 1812-2027 UT. The others do not show schedule dates yet; it looks as if two more visits are in the proposal.


That link is already in the thread. - Moderator

From the above:

We request 7 orbits of HST time to characterize this rare event. We hope that two orbits can be as soon as is feasible (Wednesday or Thursday, 22 or 23 July). We would like a second pair several days later, perhaps Saturday. We request another 2 orbits the following week. The last, seventh, orbit can be several weeks or a month later.

Another overview site:

http://planets.ucf.edu/resources/jupiter-impact

Hubble has just wrapped up its next look.


___________________________________________

Visit Status Report for 12003
Sat Aug 08 20:18:57 EDT 2009

Visit Status Targets Configs Start Time End Time
21 Archived JUPITER-IMPACT-SITE WFC3/UVIS Jul 23 2009 18:05:50 Jul 23 2009 20:36:33
22 Archived JUPITER-IMPACT-SITE-V3 WFC3/UVIS Aug 3 2009 12:59:46 Aug 3 2009 13:52:21
23 Scheduled JUPITER-IMPACT-SITE-V3 WFC3/UVIS Aug 8 2009 22:24:37 Aug 8 2009 23:20:28

This Friday 14th August, the planet Jupiter will be in opposition = best moment to observe it in binoculars or telescopes!

Is that why there are so many fantastic images of this?

Someone has contributed an amazing polar-projection animation to spaceweather.com. Hopefully this is a permalink:
http://spaceweather.com/archive.php?view=1...8&year=2009

The "zoom" version appears to show a wisp (yeah, a continent-sized "wisp) torn off into the more northerly band of weather. Very very cool.

on arXiv today The impact of a large object with Jupiter in July 2009

http://hubblesite.org/newscenter/archive/r...s/2010/16/full/

More from Hubble on lasts years impact.

Again, Anthony Wesley is not credited with the discovery by name.

The omission is especially striking in light of the press release's comments about the value of cooperation between professional and amateur astronomers.

>>"This solitary event caught us by surprise, and we can only see the aftermath of the impact, ....
>>...
>>The recent impact underscores the important work performed by amateur astronomers.
>>"This event beautifully illustrates how amateur and professional astronomers can work together..."

It's interesting that the paper noted several messages up thread, which looks as though it might be the standard scholarly account of the impact discovered by Wesley, and which is cited in the Hubble paper, includes Wesley as second author. And it's also pleasing that wikipedia says that the 2009 Jupiter impact event is "occasionally referred to as the Wesley impact."

TTT