2122 Pyatiletka

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2122 Pyatiletka
Discovery [1]
Discovered byT. Smirnova
Discovery siteCrimean Astrophysical Obs.
Discovery date14 December 1971
MPC designation(2122) Pyatiletka
Named after
(Five-Year Plans of the USSR)[2]
1971 XB · 1950 BE1
1950 DX · 1951 KB1
1954 DA · 1961 AL
1969 EV1
main-belt · (inner)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc63.18 yr (23,075 days)
Aphelion2.4729 AU
Perihelion2.3310 AU
2.4019 AU
3.72 yr (1,360 days)
0° 15m 53.28s / day
Physical characteristics
Dimensions10.75 km (calculated)[3]
11.00±0.83 km[4]
11.084±0.101 km[5]
11.554±0.074 km[6]
8.899±0.0053 h[7]
0.20 (assumed)[3]
11.759±0.002 (R)[7] · 12.1[1][4][6] · 12.21[3] · 12.40±0.29[8]

2122 Pyatiletka, provisional designation 1971 XB, is a stony asteroid from the inner regions of the asteroid belt, approximately 11 kilometers in diameter.

The asteroid was discovered on 14 December 1971, by Soviet astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula.[9] It was named for "pyatiletka", the first Five-Year Plan of the USSR.[2]

Orbit and classification[edit]

Pyatiletka orbits the Sun in the inner main-belt at a distance of 2.3–2.5 AU once every 3 years and 9 months (1,360 days). Its orbit has an eccentricity of 0.03 and an inclination of 8° with respect to the ecliptic.[1]

It was first identified as 1950 BE1 at Simeiz Observatory in 1950. The body's observation arc begins at Lowell Observatory in 1961, when it was identified as 1961 AL, 10 years prior to its official discovery observation at Nauchnyj.[9]

Physical characteristics[edit]

Pyatiletka has been characterized as a stony S-type asteroid.[3]


A fragmentary rotational lightcurve of Pyatiletka was obtained from photometric observations at the Palomar Transient Factory in California on February 2010. Lightcurve analysis gave a tentative rotation period of 8.899 hours with a brightness variation of 0.10 magnitude (U=1).[7] As of 2017, no other lightcurve has been published.[3]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Pyatiletka measures between 11.00 and 11.55 kilometers in diameter, and its surface has an albedo between 0.1931 and 0.224.[4][5][6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 10.75 kilometers with an absolute magnitude of 12.21.[3]


This minor planet was named in honor of the Five-Year Plans for the National Economy of the Soviet Union on the occasion of the 50th anniversary of its first adoption.[2] The official naming citation was published by the Minor Planet Center on 1 April 1980 (M.P.C. 5283).[10]


  1. ^ a b c d "JPL Small-Body Database Browser: 2122 Pyatiletka (1971 XB)" (2017-04-30 last obs.). Jet Propulsion Laboratory. Retrieved 11 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(2122) Pyatiletka". Dictionary of Minor Planet Names – (2122) Pyatiletka. Springer Berlin Heidelberg. p. 172. doi:10.1007/978-3-540-29925-7_2123. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g h "LCDB Data for (2122) Pyatiletka". Asteroid Lightcurve Database (LCDB). Retrieved 27 March 2017.
  4. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 27 March 2017.
  5. ^ a b c Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 27 March 2017.
  6. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
  7. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 27 March 2017.
  8. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 27 March 2017.
  9. ^ a b "2122 Pyatiletka (1971 XB)". Minor Planet Center. Retrieved 27 March 2017.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 27 March 2017.

External links[edit]