Rosetta scientific results |
Rosetta scientific results |
Sep 12 2014, 03:33 PM
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#1
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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 |
This, to my knowledge, is the first refereed paper to be published on Rosetta's observations of C-G (and it's free to access!):
The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta |
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Dec 10 2014, 08:39 PM
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#2
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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 |
just out and already making noise on the social networks:
67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio QUOTE The provenance of water and organic compounds on the Earth and other terrestrial planets has been discussed for a long time without reaching a consensus. One of the best means to distinguish between different scenarios is by determining the D/H ratios in the reservoirs for comets and the Earth’s oceans. Here we report the direct in situ measurement of the D/H ratio in the Jupiter family comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer aboard ESA’s Rosetta spacecraft, which is found to be (5.3 ± 0.7) × 10−4, that is, ~3 times the terrestrial value. Previous cometary measurements and our new finding suggest a wide range of D/H ratios in the water within Jupiter family objects and preclude the idea that this reservoir is solely composed of Earth ocean-like water.
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Dec 11 2014, 04:47 AM
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#3
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
just out and already making noise on the social networks: 67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio So here's a question. Apparently 67P was originally from the Kuiper Belt, but has been a Jupiter family comet for at least the last few centuries. A bit of googling doesn't turn up a strong estimate for when that transition occurred, though. We know that water loss by evaporation, sublimation or UV cracking can affect DE/H ratios. Could a few million years of warm/cool cycles have done this for 67P? Doug M. |
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Dec 11 2014, 06:36 AM
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#4
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Junior Member Group: Members Posts: 41 Joined: 11-April 07 From: London, U.K. Member No.: 1957 |
So here's a question. Apparently 67P was originally from the Kuiper Belt, but has been a Jupiter family comet for at least the last few centuries. A bit of googling doesn't turn up a strong estimate for when that transition occurred, though. We know that water loss by evaporation, sublimation or UV cracking can affect DE/H ratios. Could a few million years of warm/cool cycles have done this for 67P? Doug M. Yes - there is a substantial difference in vapour pressure between light and heavy water ices (Vapor pressure of ice containing D2O by Matsuo et al., 1964: 10.1126/science.145.3639.1454), which could lead to fractionation via a process such as sublimation. Indeed the fractionation factor for D2O into the ice phase increases at lower T. Since 67P gives every appearance of having a highly porous but very strong substrate, I suspect that it is a well-sintered matrix of large grains cemented together by growth from a vapour phase transported through the large (and possibly well connected network of) interstitial pores. As such, the D/H ratio may be a reflection of the degree of sintering and the thermal regime under which it occurred. |
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Dec 14 2014, 08:37 PM
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#5
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
As such, the D/H ratio may be a reflection of the degree of sintering and the thermal regime under which it occurred. Thank you -- that's very interesting. If the ratio is a function of fractionation thanks to different vapor pressures, then you'd expect it to be highest where there's been most activity already, i.e. at the surface. It does make me wonder if we might see a shift in D/H as the comet gets closer to the Sun and more active. (The assumption here is that greater activity leads to outgassing from deeper inside the comet, which of course may not be the case.) Doug M. |
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Dec 17 2014, 04:27 PM
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#6
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Junior Member Group: Members Posts: 22 Joined: 15-November 14 Member No.: 7320 |
live stream of the AGU fall meeting press conference: http://www.ustream.tv/nasajpl2
I'm sure there will also be a recording available once the live stream is over. |
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Dec 19 2014, 10:57 AM
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#7
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Member Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 |
live stream of the AGU fall meeting press conference: http://www.ustream.tv/nasajpl2 I'm sure there will also be a recording available once the live stream is over. https://virtualoptions.agu.org/category/Fal...cience/25431692 ADMIN: Requires a registration to view filed recordings. |
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Dec 19 2014, 07:42 PM
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#8
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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 |
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Dec 20 2014, 04:35 PM
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#9
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Member Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 |
Here you can view official hires ROLIS descent images:
https://virtualoptions.agu.org/media/P34B-0...tola/0_m432jt2i I don't know if now they're also available for download somewhere . ADMIN: Once again, requires a registration to view filed recordings. You obviously never bothered to look at the comments on your previous posts in this thread. |
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Dec 21 2014, 06:37 PM
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#10
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Junior Member Group: Members Posts: 22 Joined: 15-November 14 Member No.: 7320 |
The recording of the press conference can be seen on ustream.
The link mcgyver posted leads to the archive of the recorded talks at the AGU Fall Meeting last week. Yes, a registration is needed, but it's free and I have never seen free recordings from a scientific conference. As Emily Lakdawalla tweeted, the search word Rosetta gives all Rosetta/Philae related talks in the archive. Until now, 20 are listed: https://virtualoptions.agu.org/search/rosetta The registration is worth it, for example in the talk from Stefano Mottola about the ROLIS results, all seven ROLIS images of the descent of Philae are shown and the ones from the last landing site with all the colour filters. I haven't seen all talks, some are quite, say "scientific", but what have I expected? I think it's quite an opportunity to see the talks without attending the conference and without paying the conference fee. Edit: I see, links to some of the talks and the ROLIS images have been posted in the other thread. (But hearing all the information from the scientists is better than seeing just the pictures.) |
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Dec 22 2014, 12:36 AM
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#11
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Member Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 |
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Dec 24 2014, 05:26 PM
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#12
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Newbie Group: Members Posts: 4 Joined: 29-September 14 From: 28°16'7"N 16°36'20"W Member No.: 7268 |
Of course: it's the same site linked above. Same conditions apply. Thanks for stressing it. I have just tried to register and a charge of, I think, $50 was requested. I'm accessing from the Canary Islands, so perhaps that influences this? I didn't continue with registration, not because the fee is excessive but because I'm only able to access the internet via an Android tablet at present, and anything that needs Flash is not viewable. (So I was simply checking to see if the files did need Flash, as ustream does but Livestream and YouTube don't) By the way, the AGU Rosetta press conference is available on YouTube on the AGU channel. I won't try to post the link, as I assume that I will not yet have posting permission for hyperlinks. Margarita PS - later edit! I went back to the site and discovered I'd not read it properly. (Duh) The $50 is charged and then discounted !! So, no fee. I registered and have discovered that the videos are viewable on the Android tablet -------------------- "In those rare moments of total quiet with a dark sky, I again feel the awe that struck me as a child. The feeling is utterly overwhelming as my mind races out across the stars. I feel peaceful and serene."
— Dr Debra M. Elmegreen |
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Jan 22 2015, 06:57 PM
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#13
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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 |
here you go! today's Science has a first batch of Rosetta @ CG papers!
http://www.sciencemag.org/content/347/6220.toc |
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Jan 22 2015, 07:09 PM
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#14
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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 |
these two papers and their supplementary materials in particular have lots of OSIRIS imagery:
The morphological diversity of comet 67P/Churyumov-Gerasimenko On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko |
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Jan 22 2015, 07:12 PM
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#15
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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 some OSIRIS images finally online at ESA
http://www.esa.int/Our_Activities/Space_Sc...Comet_close-ups |
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