Vesta departure and journey to Ceres, A new phase of Dawn adventure |
Vesta departure and journey to Ceres, A new phase of Dawn adventure |
Dec 14 2014, 06:43 AM
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#61
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
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Dec 14 2014, 10:34 AM
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#62
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Junior Member Group: Members Posts: 78 Joined: 20-September 14 Member No.: 7261 |
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Dec 14 2014, 10:44 AM
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#63
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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 14 2014, 02:51 PM
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#64
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
at which heliocentric distance? IIRC, the delta-V for plane change(for a solar orbit) depends on the heliocentri distance Indeed it does, lets say we are to launch one dedicated mission to study Pallas, the best idea would to launch the spacecraft at an inclined orbit around the Earth of 34.8° from the very start, and then to send it on its way with the upper stage. So as for expectations, I came to the same conclusion as antipode, without having read the paper in question. Meaning that with the relatively high daytime temperature I expect Ceres to be a quite flat around the equator, but with a bit more topography, more distinct crater rims etc, toward the poles. And with brighter poles, from hoarfrost that have settled there. |
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Jan 4 2015, 02:00 AM
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#65
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Member Group: Members Posts: 808 Joined: 10-October 06 From: Maynard Mass USA Member No.: 1241 |
While we wait for DAWN to snap more approach images of Ceres, I put the Dec 2014 Framing Camera image (PIA19049) through the deconvolution process. I hate going above 10x on an image, since we are pushing around noise, point spread functions of the camera, and other artifacts (such as working from a JPEG). But I ran this baby up to the max: 30x (!)
Don't try to see craters or such things other than a bright area on the right side (and a slightly darker 'depression' on the lower right --to be named the pdp8e abyss ). Most of the image is the deconvolver 'hallucinating' about what it thinks it sees... but it is fun! The size difference (not resolution) is about what Ceres would appear at roughly 25,000 miles away -------------------- CLA CLL
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Jan 4 2015, 10:27 PM
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#66
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
@PDP8E: Yes it is really to early to see anything on Ceres yet.
But keep it up and in a little over a month we might get to see the first detail. Hubble images have hinted there is at least one surface feature that could be spotted even at the early approach. Now craters, if our current thinking is correct Ceres got a dusting of material on top, so larger (and more recent) craters might have a bright bottom. While I am at it, I am quite pessimistic on the outlook to find any satellite at Ceres for the same reason, any impact that might have sent material into orbit will be mostly be ice and might sublimate before it have time to coalescence, (which might be how the smaller satellites of Pluto came to be in that much colder environment.) There could be a very small rock in orbit, as for example one component of a binary asteroid that been captured and the small size made it escape detection in telescopic searches. |
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Jan 5 2015, 12:42 AM
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#67
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Junior Member Group: Members Posts: 78 Joined: 20-September 14 Member No.: 7261 |
"Very small rock" is a relative term - e.g. in this abstract the detection limit mentioned for various searches of Ceres' inner Hill Sphere is somewhere around 1-2 km at 4000 km, possibly bigger further in. And since Ceres' Roche limit even for the most porous of rubble piles is well below 2000 km...
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Jan 5 2015, 02:29 AM
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#68
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
Yes "relative" is the word, I were aware of those searches mentioned in the paper and with a size of just one km or two it could be more suitable to name it 'rock' here than Moon which usually make people think of a more substantial object. =)
But yes it could be somewhat larger, especially if it is exceptionally dark. |
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Mar 12 2015, 12:58 PM
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#69
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Member Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 |
Shouldn't this thread be closed now that Ceres finished its journey?
We are now talking about orbiting Ceres: http://www.unmannedspaceflight.com/index.p...mp;#entry218672 |
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