2867 Šteins
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Discovery[1]
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| Discovered by | Nikolai Stepanovich Chernykh |
| Discovery site | Crimean Astrophysical Observatory |
| Discovery date | November 4, 1969 |
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Designations
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| Named after | Kārlis Šteins |
| Alternate name(s) | 1969VC |
| Minor planet category |
Main belt |
| Epoch February 4, 2008 (JD 2454500.5) | |
| Aphelion | 405.132 Gm (2.708 AU) |
| Perihelion | 301.857 Gm (2.018 AU) |
| Semi-major axis | 353.495 Gm (2.363 AU) |
| Eccentricity | 0.146 |
| Orbital period | 1326.736 d (3.63 a) |
| Average orbital speed | 19.27 km/s |
| Mean anomaly | 259.193° |
| Inclination | 9.946° |
| Longitude of ascending node | 55.530° |
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Physical characteristics
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| Dimensions | 6.67 x 5.81 x 4.47 km[2] |
| Mean radius | 2.65 km[3] |
| Mass | ?×10? kg |
| Mean density | ? g/cm3 |
| Equatorial surface gravity | ? m/s2 |
| Escape velocity | ? km/s |
| Sidereal rotation period |
6.05 h |
| Axial tilt | ?° |
| Pole ecliptic latitude | ? |
| Pole ecliptic longitude | ? |
| Albedo | 0.34 ± 0.06 |
| Temperature | ~181 K |
| Spectral type | E |
| Absolute magnitude (H) | 12.9 |
2867 Šteins is a small main-belt asteroid that was discovered in 1969 by N. S. Chernykh.[1] It is named after Kārlis Šteins, a Latvian and Soviet astronomer.[4] Šteins was visited by the Rosetta space probe in 2008.
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[edit] Physical characteristics
A study published in 2006 by astronomers at the European Southern Observatory showed that Šteins is an E-type asteroid with a diameter of approximately 4.6 km.[5] Studying the asteroid before its flyby, the Rosetta space probe showed via a lightcurve analysis that Šteins has a rotation period of about six hours, is irregular in shape, and does not have any moons.[6]
After the Rosetta flyby, the ESA described Šteins as 'a diamond in the sky', as it has a wide body that tapers into a point. The wide section is dominated by a large crater (2.1 km diameter), which surprised scientists, who were amazed the asteroid survived such an impact.[7] The photographs of Šteins taken by Rosetta allowed scientists to determine that the asteroid has dimensions of 6.67 x 5.81 x 4.47 km,[2] which equates to a mean diameter of 5.3 km.[3]
[edit] Flyby
On September 5, 2008, the Rosetta space probe flew by Šteins at a distance of 800 kilometres and a relatively slow speed of 8.6 kilometres per second. Despite the short duration of this encounter (approximately 7 minutes in total), a great number of data could be obtained by the 15 scientific instruments operating on-board the Rosetta spacecraft.[8] This was the first of two planned asteroid flybys performed by the probe, the second being to the much larger 21 Lutetia in 2010.[9] The timing of the fly-by meant that the asteroid was illuminated by the sun from the perspective of the spacecraft, making the transmitted images clear and concise.[10] European Space Operations Centre streamed a press conference on Šteins later that day.[11]
[edit] See also
[edit] References
- ^ a b "Discovery Circumstances: Numbered Minor Planets (1)-(5000)". IAU: Minor Planet Center. http://www.cfa.harvard.edu/iau/lists/NumberedMPs000001.html. Retrieved December 29, 2008.
- ^ a b "Rosetta's OSIRIS cameras reveal the nature of asteroid Steins". ESA Science & Technology. January 8, 2010. http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=46254.
- ^ a b H. U. Keller, et all - E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta - Science 8 January 2010: Vol. 327. no. 5962, pp. 190 - 193 DOI: 10.1126/science.1179559
- ^ Schmadel, Lutz (2003). Dictionary of minor planet names (fifth ed.). Germany: Springer. p. 235. ISBN 3-540-00238-3. http://books.google.com/?id=KWrB1jPCa8AC&pg=PA235. Retrieved 2008-12-29.
- ^ S. Fornasier, I. Belskaya, M. Fulchignoni, M. A. Barucci, C. Barbieri (2006). "First albedo determination of 2867 Steins, target of the Rosetta mission". arXiv:astro-ph/0602631.
- ^ Michael Küppers, Uwe Keller, Rita Schulz, Gerhard Schwehm. "OSIRIS camera on Rosetta obtains ‘light curve’ of asteroid Steins". http://www.esa.int/SPECIALS/Rosetta/SEMCC2R08ZE_0.html.
- ^ "Steins: A diamond in the sky". ESA Rosetta News. http://www.esa.int/SPECIALS/Rosetta/SEMNMYO4KKF_0.html. Retrieved 2009-05-29.
- ^ "Encounter of a different kind: Rosetta observes asteroid at close quarters". ESA Rosetta News. http://www.esa.int/SPECIALS/Rosetta/SEM5EZO4KKF_0.html. Retrieved 2009-05-29.
- ^ M. A. Barucci, M. Fulchignoni and A. Rossi (2007). "Rosetta Asteroid Targets: 2867 Steins and 21 Lutetia". Space Science Reviews 128 (1-4): 67–78. Bibcode 2007SSRv..128...67B. doi:10.1007/s11214-006-9029-6.
- ^ "Spacecraft set for asteroid fly-by". The Press Association. September 5, 2008. http://ukpress.google.com/article/ALeqM5g_-M0-esROw8pJHo-OhQCLZWvf3w. Retrieved 2008-09-05.
- ^ "Rosetta Steins fly-by timeline". European Space Agency. September 4, 2008. http://www.spaceref.com/news/viewpr.html?pid=26345. Retrieved 2008-09-05.
[edit] External links
- ESA website with photographs and animations of Šteins
- NASA JPL Small-Body Database Browser on 2867 Steins
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