Rosetta scientific results |
Rosetta scientific results |
Feb 9 2015, 10:03 PM
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#31
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
Yep, that statement fits. The southern face should experience most of the sublimation at perihelion, but the nothern face willl be most actve in the periods before and after.
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Mar 6 2015, 01:36 PM
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#32
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Member Group: Members Posts: 813 Joined: 29-December 05 From: NE Oh, USA Member No.: 627 |
Not sure where to put this...
Introducing the NAVCAM image browser http://blogs.esa.int/rosetta/2015/03/06/in...-image-browser/ "We are happy to announce that the first set of images from Rosetta's NAVCAM has now been made available to all scientific and public users via ESA’s Planetary Science Archive (PSA). This first batch of image data covers the period leading up to 2 July 2014, prior to Rosetta’s arrival at 67P/C-G. Further releases of image data will be made in blocks on a monthly basis henceforth, with the near-term aim to catch-up so that NAVCAM data will be publicly released six months after they are taken." |
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Mar 6 2015, 02:55 PM
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#33
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Member Group: Members Posts: 219 Joined: 14-November 11 From: Washington, DC Member No.: 6237 |
Following Phil's link in another thread, looks like another batch of Rosetta papers coming soon, but of course even the abstracts are fascinating.
From agenda of European Geosciences Union General Assembly 2015 Rosetta: first results from the prime mission Lots there. |
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Mar 17 2015, 09:11 AM
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#34
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Junior Member Group: Members Posts: 27 Joined: 2-December 14 Member No.: 7359 |
From the 46th Lunar and Planetary Science Conference
http://www.hou.usra.edu/meetings/lpsc2015/pdf/sess103.pdf http://www.hou.usra.edu/meetings/lpsc2015/pdf/sess631.pdf |
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Mar 21 2015, 02:09 PM
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#35
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Senior Member Group: Members Posts: 1669 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
Regarding mass loss in the neck region they've a backdoor: If it's richer in CO2 or CO the neck region may lose mass, too. Maybe they find out more detail about the compositional variations during the close flyby to come. Is the neck region having a different composition really a sign of CG being a contact binary? Seems to me more like a single object with more ices near the center that are now exposed? This question was touched upon at a talk last evening by Joel Parker of the Southwest Research Institute (and the ALICE instrument). -------------------- Steve [ my home page and planetary maps page ]
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Mar 21 2015, 05:58 PM
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#36
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
A contact binary would probably be more interesting, but I share your preference for exposure of fresh interiour material of a single object.
Once the outermost crust is lost, sublimation may progress faster in that area, resulting in forming the neck. The sublimation process of a prestine rotating cometary nucleus may start either near the equator for a spin axis parallel to the orbital axis, or near one of the poles if the pole happens to be directed towards the Sun near perihelion (skipping other options). Taking the equator version the rotation axis may change (or precess) due to a change of the axis of maximum moment of inertia due to preferred mass loss of the nucleus near the equator. |
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Mar 21 2015, 06:09 PM
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#37
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Senior Member Group: Members Posts: 1669 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
This preferential sublimation process seems interesting to me in for example how it might be modeled. Good food for thought with Gerald's scenarios. It also seems plausible in explaining some other similarly shaped comets.
-------------------- Steve [ my home page and planetary maps page ]
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Mar 22 2015, 03:54 AM
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#38
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Member Group: Members Posts: 148 Joined: 9-August 11 From: Mason, TX Member No.: 6108 |
What still keeps me from accepting the excavated neck story are the large pits on the main body that are closest to the crack in the neck. These have the appearance of some of the other vent pits on both bodies. If they are indeed expired vents, then they had to have formed earlier than the scree/talus that now spills into them from the head. They do not match the valley wall morphology further up the neck; they are positioned facing outward relative to the main body, and circular as if not influenced by earlier neck material. I just can't conceive a history of their formation relative to neck material deflation that would have been happening at the same time, were this a unified object rather than a piece rotated into place at a later era. I see the refill history of those pits as telling something about the sequence of activity/erosion in the neck.
-------------------- --
Don |
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Mar 22 2015, 08:03 AM
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#39
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
BTW, if you have access to Science the nitrogen discovery paper is here:
Molecular nitrogen in comet 67P/Churyumov-Gerasimenko indicates a low formation temperature |
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Mar 22 2015, 08:13 PM
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#40
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Member Group: Members Posts: 334 Joined: 11-December 12 From: The home of Corby Crater (Corby-England) Member No.: 6783 |
I was thinking about the 'Contact Binary. and the 'Eroded Neck' theories going on and thought I would add my twopence worth in favour of the 'Eroded Neck. camp.
While browsing here http://blogs.esa.int/rosetta/2015/03/20/co...-6-hours-later/ This image and this comment "On the large lobe, another striking feature catches the eye: the Aten region, an elongated depression between Ash, to the left, and Khepry, to the right." The difference between the smoother,elongated. central region compared to the left and right regions on the larger lobe, to my eye, also applies to the smaller lobe. This would indicate the same process happened to both lobes together. In other words they are the same object. |
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Mar 25 2015, 01:42 PM
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#41
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Junior Member Group: Members Posts: 25 Joined: 22-November 14 Member No.: 7349 |
I'm not sure I understand that reasoning. If we assume that the perihelion passages reforms the surface of the bodies, then the main surface features of both lobes would have been shaped by the same process at the same time regardless of whether it's a contact binary or not. If it is a binary object then they presumably joined before becoming a comet after all. It might indicate that both lobes have similar/same composition, but not that 67p is necessarily a single object.
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Mar 25 2015, 07:14 PM
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#42
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Member Group: Members Posts: 334 Joined: 11-December 12 From: The home of Corby Crater (Corby-England) Member No.: 6783 |
Fair point!
The ratio between central area and left/right, also seems similar between the two lobes.....mmmmmmm... So your rationale seems plausible for a contact binary. (As do others) Lucky it's only twopence, but that's the beauty of armchair exploration. Game on !! |
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Apr 13 2015, 09:12 AM
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#43
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Junior Member Group: Members Posts: 78 Joined: 20-September 14 Member No.: 7261 |
Since we had a link to AGU webstreaming here's the European counterpart, albeit only with a single press conference streamed for Rosetta:
http://client.cntv.at/egu2015/PC1 Ulamec, Taylor and the PIs of ROMAP and RPC-MAG. Live on Tuesday, 1200 to 1300 UTC+2 (CEST). Before that the stream will show previous press conferences (and something that looks like standup comedy in the press conference room in Austrian inbetween ) The above stream link offers a chat function to submit questions for the press conference remotely. Related speech at EGU 2015: http://meetingorganizer.copernicus.org/EGU2015/session/17358 Abstracts for all speeches on Rosetta at EGU 2015 today and tomorrow: http://meetingorganizer.copernicus.org/EGU2015/orals/17358 And, perhaps oddly, abstracts for the poster session: http://meetingorganizer.copernicus.org/EGU2015/posters/17358 (edit: those two already posted earlier in this thread, here for completeness.) |
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Apr 14 2015, 12:29 PM
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#44
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Junior Member Group: Members Posts: 25 Joined: 22-November 14 Member No.: 7349 |
Thank you for the heads up katodomo, the stream is over but a video is now available. It deals mostly with Philae and the magnetic field of the comet, magnetic field information is also in a new Rosetta blog post (http://blogs.esa.int/rosetta/2015/04/14/ro...not-magnetised/).
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Apr 14 2015, 04:27 PM
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#45
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
and the Science preprint: The nonmagnetic nucleus of comet 67P/Churyumov-Gerasimenko
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