Wikipedia

2867 Šteins

2867 Šteins (provisional designation 1969 VC) is an irregular, diamond-shaped background asteroid from the inner regions of the asteroid belt, approximately 5 kilometers (3.1 miles) in diameter. It was discovered on 4 November 1969 by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij on the Crimean peninsula.[1] In September 2008, ESA's spacecraft Rosetta flew by Šteins, making it one of few minor planets ever visited by a spacecraft. The bright E-type asteroid features 23 named craters and has a rotation period of 6.05 hours.[8] It was named for Soviet Latvian astronomer Kārlis Šteins.[1]

2867 Šteins
Šteins imaged by Rosetta
Discovery [1]
Discovered byN. Chernykh
Discovery siteCrimean Astrophysical Obs.
Discovery date4 November 1969
Designations
(2867) Šteins
Pronunciation/ˈsteɪns/
Named after
Kārlis Šteins [1]
  • 1969 VC
  • 1954 QL
  • 1979 FJ4
  • 1980 VV1
  • 1980 WB
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc66.47 yr (24,279 d)
Aphelion2.7081 AU
Perihelion2.0185 AU
2.3633 AU
Eccentricity0.1459
3.63 yr (1,327 d)
182.24°
0° 16m 16.68s / day
Inclination9.9354°
55.366°
251.08°
Physical characteristics
Dimensions6.83 km × 5.70 km × 4.42 km[5]
4.92±0.40 km[6]
5.160±0.167 km[7]
6.049 h[8][a]
0.300[7]
0.34[6]
0.40[5][9][10]
E [8][9][11]
V–R = 0.510±0.030[12][13]
12.7[1][2]
13.36[8][7]
13.36±0.07[6]

Orbit and classification

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Šteins is a non-family asteroid from the main belt's background population.[3][4] It orbits the Sun in the inner asteroid belt at a distance of 2.0–2.7 AU once every 3 years and 8 months (1,327 days; semi-major axis of 2.36 AU). Its orbit has an eccentricity of 0.15 and an inclination of 10° with respect to the ecliptic.[2] The body's observation arc begins with a precovery, taken at the Palomar Observatory in November 1951, or 18 years prior to its official discovery observation.[1]

Naming

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This minor planet was named in memory of Kārlis Šteins (1911–1983), a Latvian and Soviet astronomer. He was a long-time observatory director at the University of Latvia in Riga and designed astronomical instruments. Šteins is known for his work on cometary cosmogony and the study of Earth's rotation.[1] The official naming citation was published by the Minor Planet Center on 18 September 1986 (M.P.C. 11157).[14]

Features on Šteins

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Further information: List of craters on Šteins

On 11 May 2012, IAU's Working Group for Planetary System Nomenclature announced a naming system for geographical features on Šteins.[15] Inspired by the asteroid's gem-like shape, its crater are given the English-language names of precious stones, with the largest being named Diamond crater (see below).

Except for the montes of Mercury and the lunar maria (and proposed for 2 Pallas and 7 Iris), the craters of Šteins are the only features in the Solar System whose names are not derived from proper nouns.[16] In addition, a distinct region on the asteroid has been named Chernykh Regio after the discoverer, Nikolai Chernykh.[17]

Physical characteristics

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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 kilometers.[9] 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 the large Diamond crater with a diameter of 2.1 kilometers, which surprised scientists, who were at first amazed the asteroid survived such an impact,[18] while later it turned out that the crater-to-body diameter ratio of 0.79 is in fact not abnormally large as it follows an already established trend.[19] Besides its irregular in shape, it does not have any moons.[20]

Diameter and albedo

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According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer and observations by the Spitzer Space Telescope, Šteins measures 5.16 and 4.92 kilometers in diameter and its surface has an albedo of 0.30 and 0.34, respectively.[6][7] Its overall Bond albedo is 0.24 ± 0.01.[21] In 2012, the photographs of Šteins taken by Rosetta using stereophotoclinometry allowed scientists to determine that the asteroid's dimensions are 6.83 × 5.70 × 4.42 kilometers, which equates to a mean diameter in volume of 5.26 km.[5] (Asteroid 129167 Dianelambert was later named for the scientist using this 3D-method.) The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.34 and a diameter of 4.9 kilometers with an absolute magnitude of 13.36.[8]

Lightcurves and poles

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Studying the asteroid with Rosetta space probe onboard OSIRIS cameras shortly before its flyby showed via a lightcurve analysis that Šteins has a rotation period of 6.052±0.007 hours.[22][20] The results of the rotational lightcurve agree with ground-based photometric observations of Šteins with a period of 6.049 hours and a brightness amplitude between 0.18 and 0.31 magnitude (U=3/3).[8][10][12][13][23][24][a]

A lightcurve inversion also modeled a concurring sidereal period of 6.04681 hours and determined a spin axis at (250.0°, −89.0°) in ecliptic coordinates (λ, β). The modeling was done by compiling a set of 26 previously obtained visible lightcurves.[25]

Exploration

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Rosetta flyby

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Animation of Rosetta's trajectory from 2 March 2004 to 9 September 2016
   Rosetta  ·   67P ·   Earth ·   Mars ·   21 Lutetia  ·   2867 Šteins

On 5 September 2008, the Rosetta space probe flew by Šteins at a distance of 800 km and a relatively slow speed of 8.6 km/s. Despite the short duration of this encounter (approximately 7 minutes in total), a great amount of data was obtained by the 15 scientific instruments operating on board the Rosetta spacecraft.[26] This was the first of two planned asteroid flybys performed by the probe, the second being to the much larger 21 Lutetia in 2010.[27] 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. The European Space Operations Centre streamed a press conference on Šteins later that day.[28]

See also

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Notes

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  1. ^ a b Lightcurve plot of 2867 Steins, Palmer Divide Observatory by B. D. Warner (2004). Rotation period of 6.05±0.01 hours with a brightness amplitude of 0.30 mag. Quality code is 3-. Summary figures for (2867) Šteins at the LCDB.

References

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  1. ^ a b c d e f g h "2867 Steins (1969 VC)". Minor Planet Center. Retrieved 31 August 2018.
  2. ^ a b c d "JPL Small-Body Database Browser: 2867 Steins (1969 VC)" (19 May 2018 last obs.). Jet Propulsion Laboratory. Retrieved 31 August 2018.
  3. ^ a b "Asteroid (2867) Steins – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 31 August 2018.
  4. ^ a b "Asteroid 2867 Steins". Small Bodies Data Ferret. Retrieved 31 August 2018.
  5. ^ a b c Jorda, L.; Lamy, P. L.; Gaskell, R. W.; Kaasalainen, M.; Groussin, O.; Besse, S.; et al. (November 2012). "Asteroid (2867) Steins: Shape, topography and global physical properties from OSIRIS observations". Icarus. 221 (2): 1089–1100. Bibcode:2012Icar..221.1089J. doi:10.1016/j.icarus.2012.07.035.
  6. ^ a b c d Lamy, P. L.; Jorda, L.; Fornasier, S.; Groussin, O.; Barucci, M. A.; Carvano, J.; et al. (September 2008). "Asteroid 2867 Steins. III. Spitzer Space Telescope observations, size determination, and thermal properties". Astronomy and Astrophysics. 487 (3): 1187–1193. Bibcode:2008A&A...487.1187L. doi:10.1051/0004-6361:20078996.
  7. ^ a b c d Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System: EAR-A-COMPIL-5-NEOWISEDIAM-V1.0. Bibcode:2016PDSS..247.....M. Retrieved 31 August 2018.
  8. ^ a b c d e f "LCDB Data for (2867) Šteins". Asteroid Lightcurve Database (LCDB). Retrieved 31 August 2018.
  9. ^ a b c Fornasier, S.; Belskaya, I.; Fulchignoni, M.; Barucci, M. A.; Barbieri, C. (April 2006). "First albedo determination of 2867 Steins, target of the Rosetta mission". Astronomy and Astrophysics. 449 (2): L9–L12. arXiv:astro-ph/0602631. Bibcode:2006A&A...449L...9F. doi:10.1051/0004-6361:20064913. S2CID 14039220.
  10. ^ a b Hicks, M. D.; Bauer, J. M.; Tokunaga, A. T. (April 2004). "(2867) Steins IAUC 8315". IAU Circ. 8315 (8315): 3. Bibcode:2004IAUC.8315....3H. Retrieved 31 August 2018.
  11. ^ Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; et al. (March 2017). "Refining the asteroid taxonomy by polarimetric observations". Icarus. 284: 30–42. Bibcode:2017Icar..284...30B. doi:10.1016/j.icarus.2016.11.003. hdl:11336/63617.
  12. ^ a b Weissman, Paul R.; Lowry, Stephen C.; Choi, Young-Jun (August 2005). "CCD Photometry of Asteroid 2867 Steins: Flyby Target of the Rosetta Mission". American Astronomical Society. 37: 644. Bibcode:2005DPS....37.1528W.
  13. ^ a b Dotto, E.; Perna, D.; Fornasier, S.; Belskaya, I. N.; Barucci, M. A.; Shevchenko, V. G.; et al. (February 2009). "Photometric and spectroscopic investigation of 2867 Steins, target of the Rosetta mission. Ground-based results prior to the Rosetta fly-by". Astronomy and Astrophysics. 494 (3): L29–L32. Bibcode:2009A&A...494L..29D. doi:10.1051/0004-6361:200811340.
  14. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 31 August 2018.
  15. ^ "First Names Approved for Asteroid (2867) Steins". USGS–Astrogeology Science Center. Retrieved 14 September 2015.
  16. ^ "Gazetteer of Planetary Nomenclature–Categories for Naming Features on Planets and Satellites". IAU–Working Group for Planetary System Nomenclature (WGPSN). Retrieved 14 September 2015.
  17. ^ "Target: Steins". IAU–Working Group for Planetary System Nomenclature (WGPSN). Archived from the original on 3 October 2018. Retrieved 14 September 2015.
  18. ^ "Steins: A diamond in the sky". ESA Rosetta News. Retrieved 29 May 2009.
  19. ^ Burchell, M. J.; Leliwa-Kopystynski, J. (December 2010). "The large crater on the small Asteroid (2867) Steins". Icarus. 210 (2): 707–712. Bibcode:2010Icar..210..707B. doi:10.1016/j.icarus.2010.07.026. S2CID 123554130. Retrieved 31 August 2018.
  20. ^ a b Michael Küppers; Uwe Keller; Rita Schulz; Gerhard Schwehm (20 March 2007). "OSIRIS camera on Rosetta obtains 'light curve' of asteroid Steins". European Space Agency. Retrieved 31 August 2018.
  21. ^ Spjuth, S.; Jorda, L.; Lamy, P. L.; Keller, H. U.; Li, J.-Y. (November 2012). "Disk-resolved photometry of Asteroid (2867) Steins". Icar. 221 (2): 1101–1118. Bibcode:2012Icar..221.1101S. doi:10.1016/j.icarus.2012.06.021. ISSN 0019-1035.
  22. ^ Küppers, M.; Mottola, S.; Lowry, S. C.; A'Hearn, M. F.; Barbieri, C.; Barucci, M. A.; et al. (January 2007). "Determination of the light curve of the Rosetta target asteroid (2867) Steins by the OSIRIS cameras onboard Rosetta". Astronomy and Astrophysics. 462 (1): L13–L16. arXiv:astro-ph/0612097. Bibcode:2007A&A...462L..13K. doi:10.1051/0004-6361:20066694. S2CID 14097820.
  23. ^ Warner, Brian D. (September 2004). "Lightcurve analysis for numbered asteroids 301, 380, 2867, 8373, 25143, and 31368". The Minor Planet Bulletin. 31 (3): 67–70. Bibcode:2004MPBu...31...67W. ISSN 1052-8091.
  24. ^ Weissman, P. R.; Lowry, S. C.; Choi, Y.-J. (May 2007). "Photometric observations of Rosetta target asteroid 2867 Steins". Astronomy and Astrophysics. 466 (2): 737–742. arXiv:astro-ph/0702339. Bibcode:2007A&A...466..737W. doi:10.1051/0004-6361:20066409. S2CID 2255678.
  25. ^ Lamy, P. L.; Kaasalainen, M.; Lowry, S.; Weissman, P.; Barucci, M. A.; Carvano, J.; et al. (September 2008). "Asteroid 2867 Steins. II. Multi-telescope visible observations, shape reconstruction, and rotational state". Astronomy and Astrophysics. 487 (3): 1179–1185. Bibcode:2008A&A...487.1179L. doi:10.1051/0004-6361:20078995.
  26. ^ "Encounter of a different kind: Rosetta observes asteroid at close quarters". ESA Rosetta News. Archived from the original on 10 May 2009. Retrieved 29 May 2009.
  27. ^ M. A. Barucci; M. Fulchignoni & 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. S2CID 123088075.
  28. ^ Talevi, Monica (4 September 2008). "Rosetta Steins fly-by timeline". European Space Agency. Retrieved 5 September 2008.[permanent dead link‍]
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