Rosetta scientific results |
Rosetta scientific results |
Sep 12 2014, 03:33 PM
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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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Jan 29 2015, 07:13 PM
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Member Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 |
I think nobody is talking about this here, but I think it's an amazing scientific result: Rosetta detected 350 micro-asteroids orbiting around 67P!!
QUOTE considering measurements made with both GIADA and OSIRIS on 4 August 2014, when we were still at 275 km from the comet. These observations allowed us to count about 350 grains in bound orbits around the comet nucleus, and 48 fast, out-flowing grains that were ejected about a day before the observations. http://blogs.esa.int/rosetta/2015/01/22/gi...nts-3-7-3-4-au/ Supplemental material gives more details: microsatellites were detected not by the dust grain detector (GIADA) but by the OSIRIS camera: QUOTE We consider OSIRIS-NAC images (2048 x 2048 px) taken on 4 August 2014 from 3h49UT to 5h53UT at 3.6 AU from the Sun. These images are taken in sets repeated 5 times, with an interval of 26 minutes between each set. Each of these 5 sets contains 5 images with an exposure of 17.25 s taken every minute using the NAC's orange filter (centred on 649 nm, 84.5 nm wide). (so we have at least 25 hires images awaiting for release ) QUOTE In the composite image, covering a time interval of 197.25 s, every moving object appears as a sequence of white, black, white and black tracks (fast moving grains) or dots (slow moving grains), thus allowing us to define its apparent speed and direction of motion QUOTE . Assuming a mean albedo of 5%, we get a diameter range from 0.2 to 2 m for grains at the outermost limit of the grain cloud (at about 600 km from the spacecraft; the size of 2 m is a crude upper limit: it assumes that the brightest grains are also the farthest); and from 4 to 40 cm for grains at 130 km from the spacecraft
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