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Rosetta flyby of Asteroid Steins, 5th September 2008
peter59
post Jun 19 2008, 06:53 AM
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Only 78 days to Stein encounter ! I can't believe I forgot about this event.


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Paolo
post Jun 21 2008, 09:23 AM
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Some details about Steins that I collected for the third volume of my book "robotic exploration of the solar system"

Steins is a small body less than 10 km across, discovered on 4 November 1969 by Soviet astronomer N. Chernykh at the Nauchnyj Observatory in Crimea and named after Karlis Steins, former director of the Latvian University Astronomical Observatory. While the properties of Lutetia, the second asteroid target are relatively well known, being a largish and bright object discovered more than a century ago, almost nothing was known about Steins, and observational campaigns were started in 2004 to characterize it. Steins was observed by the largest astronomical observatory on Earth, including the European Very Large Telescope (VLT) in Chile, JPL's Table Mountain Observatory, the Spitzer infrared astronomy satellite and Rosetta itself.
The Rosetta orbiter observed continuously Steins (1.06 AU away) for 24 hours with its science camera on 11 March 2006 in order to collect a “light curve” at phase angles larger than ever achievable from Earth, due to observational geometry constrains and for a longer time span, uninterrupted by day and night cycles. A total of 238 images were taken, covering four rotations.
Although researchers initially catalogued Steins in the S class (like most previously-visited bodies), the observational campaigns found that its spectral and polarimetric properties placed it in the E taxonomic class of reddish bodies with high albedo believed to be thermally evolved and of igneous origin, which underwent at least a partial melting and differentiation early in their history. E asteroid spectra probably makes them related to some rare enstatite chondrite or aubrite meteorites and therefore these bodies are believed to have a surface consisting of iron-free or iron-poor silicates. Observations pinpointed Steins' rotation period at about 6.05 hours, while the measured diameter could vary between 2 and 5 km, depending on its albedo. Asymmetries in the light curve confirmed that the small body has an irregular shape, with a ratio between the main axes of about 1.3. Other researchers pointed out that some of the characteristics of Steins could hint at a young and very rough surface at most a few million years old.
While fewer than 30 members of the E class of asteroids were known, including (44) Nysa, the largest, and two near-Earth objects, (3103) Eger and (4660) Nereus (a recurrent space mission target), little is known about the evolutionary history of the type. Steins was initially placed in the same family as (64) Angelina, but other studies showed that it shared most of the same spectral characteristics as Eger, both bodies being believed to be members of an old eroded family which formed in the inner asteroid belt close to the present position of Steins, which appears to be the largest member of the family. The presence of Eger in an Earth-intersecting orbit of course provides a path for enstatite and aubrite meteorites to hit our planet.
The encounter on 5 September 2008 will be at a distance of 1745 km and a relative speed of 8.6 km/s
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- peter59   Rosetta flyby of Asteroid Steins   Jun 19 2008, 06:53 AM
- - dmuller   Indeed, almost there ... 78 days and 121 million k...   Jun 19 2008, 09:00 AM
|- - plasmatorus   QUOTE (dmuller @ Jun 19 2008, 02:00 AM) I...   Jul 28 2008, 04:45 PM
- - ugordan   QUOTE (peter59 @ Jun 19 2008, 08:53 AM) O...   Jun 19 2008, 09:05 AM
|- - peter59   QUOTE (ugordan @ Jun 19 2008, 09:05 AM) A...   Jun 19 2008, 10:01 AM
|- - ugordan   QUOTE (peter59 @ Jun 19 2008, 12:01 PM) P...   Jun 19 2008, 10:47 AM
- - jasedm   Perhaps it's time for a dedicated 'Steins...   Jun 19 2008, 10:11 AM
- - djellison   They had previously been announced ( both of them,...   Jun 19 2008, 10:58 AM
- - Paolo   Some details about Steins that I collected for the...   Jun 21 2008, 09:23 AM
- - IM4   Even more details for Rosetta fans !!...   Jun 21 2008, 10:04 AM
- - tasp   Do we have any radar data indicating binary/satel...   Jun 21 2008, 11:35 AM
|- - nprev   QUOTE (tasp @ Jun 21 2008, 03:35 AM) Do w...   Jun 21 2008, 05:00 PM
||- - tedstryk   QUOTE (nprev @ Jun 21 2008, 05:00 PM) Was...   Jun 21 2008, 08:39 PM
|- - jasedm   QUOTE (tasp @ Jun 21 2008, 12:35 PM) Do w...   Jun 25 2008, 04:21 PM
|- - cotopaxi   QUOTE (jasedm @ Jun 25 2008, 05:21 PM) I ...   Jul 14 2008, 03:36 AM
- - gpurcell   These sort of encounters always fascinate me...thi...   Jun 21 2008, 03:31 PM
|- - centsworth_II   QUOTE (gpurcell @ Jun 21 2008, 11:31 AM) ...   Jun 21 2008, 04:16 PM
- - tasp   Thanx for the article! An idea springs to min...   Jun 25 2008, 05:21 PM
- - tty   Certainly there are earth-crossing binaries. There...   Jun 25 2008, 06:57 PM
- - cosmo   Around 15% or even more of the NEAs are suspected ...   Jun 29 2008, 10:15 AM
- - Rakhir   Rosetta awakes from hibernation for asteroid encou...   Jul 3 2008, 09:50 PM
- - charborob   I've been doing some calculations. Rosetta...   Jul 4 2008, 02:35 PM
|- - tedstryk   To be fair, Gaspra is a much bigger asteroid - 18...   Jul 4 2008, 07:16 PM
- - charborob   In my post, I was just trying to give an idea of w...   Jul 4 2008, 08:49 PM
- - Ken90000   The Cool thing about 2867 Steins is its type. We ...   Jul 7 2008, 08:17 PM
- - dvandorn   Let us hope that ESA doesn't do the same thing...   Jul 8 2008, 04:11 AM
|- - ugordan   QUOTE (dvandorn @ Jul 8 2008, 06:11 AM) L...   Jul 8 2008, 07:29 AM
- - djellison   Crime 1. Not sequencing a normal RGB sequence dur...   Jul 8 2008, 11:45 AM
|- - ugordan   Crime 2 definitely stands. It's ironic that th...   Jul 8 2008, 11:55 AM
- - tasp   The article indicates light curve data was taken f...   Jul 14 2008, 12:56 PM
|- - cotopaxi   Full quote of previous post removed - mods OSIRIS...   Jul 15 2008, 03:59 AM
- - tasp   IIRC, a craft will eventually return to Tempel 1, ...   Jul 15 2008, 12:18 PM
|- - tedstryk   And that couldn't be done from earth because w...   Jul 15 2008, 01:43 PM
- - tasp   I am just trying to find activities for NH when it...   Jul 15 2008, 02:04 PM
|- - ugordan   QUOTE (tasp @ Jul 15 2008, 04:04 PM) Nix ...   Jul 15 2008, 02:23 PM
- - dmuller   Thanks plasmatorus for the flyby time and Emily fo...   Jul 29 2008, 10:49 AM
- - Paolo   Note that there are three papers on Steins for pub...   Aug 2 2008, 05:51 PM
|- - Paolo   the three papers are now available. I guess this i...   Aug 12 2008, 12:01 PM
- - remcook   Optical tracking has started (includes image of St...   Aug 4 2008, 12:20 PM
|- - cotopaxi   I am not sure what exactly is unclear, but let me ...   Aug 4 2008, 01:09 PM
- - remcook   thanks for the explanation. sorry, my confusion wa...   Aug 4 2008, 01:25 PM
|- - cotopaxi   Ah, ok, yes, that's confusing. It guess it is ...   Aug 5 2008, 08:26 AM
- - remcook   Thanks again, much appreciated! Looking forwar...   Aug 5 2008, 08:37 AM
- - jasedm   The discoverer of Steins died a few years back, bu...   Aug 12 2008, 12:32 PM
- - cndwrld   Here is some information on the flyby. I tried to ...   Aug 13 2008, 08:57 AM
|- - mchan   Thanks for posting this description. QUOTE (cndwr...   Aug 14 2008, 01:44 AM
- - cndwrld   QUOTE Hope to see lots of images then. Ahhh, don...   Aug 14 2008, 07:22 AM
- - cndwrld   nth Asteroid Flyby I was wondering about this que...   Aug 18 2008, 07:49 AM
- - djellison   Ones I can think of Galileo did Gaspera, then Ida...   Aug 18 2008, 09:17 AM
|- - elakdawalla   QUOTE (djellison @ Aug 18 2008, 01:17 AM)...   Aug 25 2008, 03:47 AM
|- - stevesliva   QUOTE (elakdawalla @ Aug 24 2008, 11:47 P...   Aug 25 2008, 04:07 AM
- - PhilCo126   Don't forget Hayabusa... and the cometary fly-...   Aug 18 2008, 11:19 AM
|- - djellison   Hayabusa was a rendezvous and orbit, and well, a c...   Aug 18 2008, 11:58 AM
- - cotopaxi   Some information and images from the navigation ca...   Aug 18 2008, 04:41 PM
- - tasp   I recall Carl Sagan finding difficulty in scheduli...   Aug 18 2008, 11:42 PM
|- - tallbear   QUOTE (tasp @ Aug 18 2008, 03:42 PM) I re...   Aug 19 2008, 07:41 AM
|- - ugordan   Well, "closer looks" is a bit misleading...   Aug 19 2008, 08:20 AM
- - jasedm   This is a great way of characterising the small mo...   Aug 19 2008, 08:24 AM
|- - JRehling   FWIW, of all of the small inner satellites of Satu...   Aug 19 2008, 06:34 PM
- - PhilCo126   Stardust is still on route for another flyby with ...   Aug 19 2008, 05:46 PM
- - PhilCo126   Correction Emily; a single-image version of Your ...   Aug 25 2008, 09:24 AM
- - jasedm   I second that sentiment - nice job Emily. It's...   Aug 25 2008, 02:45 PM
- - peter59   The closest approach to Steins is due to take plac...   Aug 25 2008, 07:33 PM
- - PhilCo126   Rosetta blog: http://webservices.esa.int/blog/blog...   Sep 2 2008, 12:37 PM
|- - stewjack   ESA Spacecraft Operations News Timeline of nomin...   Sep 2 2008, 04:25 PM
|- - peter59   QUOTE (stewjack @ Sep 2 2008, 05:25 PM) D...   Sep 2 2008, 04:35 PM
- - djellison   Ahh - good stuff - I thought the last Earth flyby ...   Sep 2 2008, 12:55 PM
- - stewjack   This Coverage of Rosetta Steins fly-by will probab...   Sep 4 2008, 06:42 PM
|- - climber   Unnecessary full inline quote removed - mod. The ...   Sep 5 2008, 06:38 PM
- - PhilCo126   For the Press conference, also: http://www.esa.int...   Sep 5 2008, 11:38 AM
- - dmuller   Closest approach now just over 1 hr 15 minutes awa...   Sep 5 2008, 05:26 PM
|- - ElkGroveDan   QUOTE We just had a quick chat with Spacecraft Ope...   Sep 5 2008, 05:32 PM
- - imipak   Climber - if stewjack's got it wrong then so h...   Sep 5 2008, 07:22 PM
|- - climber   QUOTE (imipak @ Sep 5 2008, 09:22 PM) Cli...   Sep 5 2008, 09:11 PM
|- - tedstryk   So, no images yet. I take it ESA is hiding behind...   Sep 5 2008, 10:50 PM
- - Hungry4info   Definitely looking forward to some images ^_^ I...   Sep 5 2008, 10:58 PM
- - elakdawalla   Hungry4info: Here's my favorite Web resource ...   Sep 5 2008, 11:43 PM
|- - Hungry4info   QUOTE (elakdawalla @ Sep 5 2008, 05:43 PM...   Sep 5 2008, 11:57 PM
|- - climber   QUOTE (Hungry4info @ Sep 6 2008, 01:57 AM...   Sep 6 2008, 06:43 AM
|- - ustrax   Dear Ted...you MUST admit that things are changing...   Sep 6 2008, 07:39 AM
|- - tedstryk   QUOTE (ustrax @ Sep 6 2008, 08:39 AM) Dea...   Sep 6 2008, 09:04 AM
|- - ustrax   QUOTE What is "I type" asteroid??? Toma...   Sep 6 2008, 09:11 AM
- - volcanopele   Sure I might as well. Now taking bets on the obje...   Sep 6 2008, 12:28 AM
|- - elakdawalla   QUOTE (volcanopele @ Sep 5 2008, 05:28 PM...   Sep 6 2008, 02:11 AM
- - tasp   Itokawa and Eros had a love child with a bad attit...   Sep 6 2008, 01:01 AM
- - dvandorn   Potato. Definitely potato. -the other Doug   Sep 6 2008, 02:28 AM
- - ElkGroveDan   I'll say a yam.   Sep 6 2008, 02:56 AM
- - vjkane   since all the obvious ones are taken, Snoopy!   Sep 6 2008, 03:38 AM
|- - Hungry4info   QUOTE (vjkane @ Sep 5 2008, 09:38 PM) sin...   Sep 6 2008, 04:39 AM
- - lyford   QUOTE It's incredible!Flight Director Paol...   Sep 6 2008, 04:03 AM
- - nprev   Okay...I'm gonna go with "fat-hockey-puck...   Sep 6 2008, 05:43 AM
- - lyford   GO USTRAX!!!! Of course, it...   Sep 6 2008, 07:42 AM
|- - ustrax   QUOTE (lyford @ Sep 6 2008, 08:42 AM) GO ...   Sep 6 2008, 07:47 AM
- - Philotas   From their blog: QUOTE Good morning! The fi...   Sep 6 2008, 07:44 AM
|- - Rakhir   QUOTE (Philotas @ Sep 6 2008, 08:44 AM) F...   Sep 6 2008, 08:41 AM
- - Tman   Hehe, would be cool if it's congruent with the...   Sep 6 2008, 07:59 AM
- - lyford   Crikey! 1:45 am PST and some Cabernet Franc te...   Sep 6 2008, 08:50 AM
- - Toma B   What is "I type" asteroid??? QUOTE Good...   Sep 6 2008, 09:01 AM
- - Toma B   This is what we were expecting? QUOTE Size_______...   Sep 6 2008, 09:07 AM
- - climber   Press conf in less than 10 minutes   Sep 6 2008, 09:50 AM
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