2867 Šteins
From Wikipedia, the free encyclopedia
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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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| Alternate name | |
| 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 | ~2 to ~5 km |
| 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 | 0.10 |
| 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.[2]
A recent study by astronomers at the European Southern Observatory showed that Šteins is an E-type asteroid with a diameter of approximately 4.6 km.[3] A lightcurve analysis by the Rosetta space probe has shown that Šteins has a rotation period of about six hours, is irregular in shape, and does not have any moon.[4]
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[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.[5] This was the first of two planned asteroid flybys performed by the probe, the second being the much larger 21 Lutetia in 2010.[6] 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.[7] European Space Operations Centre streamed a press conference on Šteins later that day.[8]
[edit] Physical characteristics
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, which surprised scientists, who were amazed the asteroid survived such an impact.[9]
[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 on December 29, 2008.
- ^ Schmadel, Lutz (2003). Dictionary of minor planet names (fifth ed.). Germany: Springer. p. 235. ISBN 3-540-00238-3. http://books.google.com/books?id=KWrB1jPCa8AC&pg=PA235. Retrieved on 2008-12-29.
- ^ S. Fornasier, I. Belskaya, M. Fulchignoni, M. A. Barucci, C. Barbieri. "First albedo determination of 2867 Steins, target of the Rosetta mission". http://fr.arxiv.org/abs/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.
- ^ "Encounter of a different kind: Rosetta observes asteroid at close quarters". ESA Rosetta News. http://www.esa.int/SPECIALS/Rosetta/SEM5EZO4KKF_0.html. Retrieved on 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. doi:.
- ^ "Spacecraft set for asteroid fly-by". The Press Association. September 5, 2008. http://ukpress.google.com/article/ALeqM5g_-M0-esROw8pJHo-OhQCLZWvf3w. Retrieved on 2008-09-05.
- ^ "Rosetta Steins fly-by timeline". European Space Agency. September 4, 2008. http://www.spaceref.com/news/viewpr.html?pid=26345. Retrieved on 2008-09-05.
- ^ "Steins: A diamond in the sky". ESA Rosetta News. http://www.esa.int/SPECIALS/Rosetta/SEMNMYO4KKF_0.html. Retrieved on 2009-05-29.
[edit] External links
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