# 2122 Pyatiletka

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{{Short description|Stony asteroid}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
 | minorplanet     = yes
 | name            = 2122 Pyatiletka
 | background      = #D6D6D6
 | image           = 
 | image_size      = 
 | caption         = 
 | discovery_ref   = <ref name="jpldata" />
 | discovered      = 14 December 1971
 | discoverer      = [T. Smirnova](/source/Tamara_Smirnova)
 | discovery_site  = {{nowrap|[Crimean Astrophysical Obs.](/source/Crimean_Astrophysical_Observatory)}}
 | mpc_name        = (2122) Pyatiletka
 | alt_names       = 1971 XB{{·}}{{mp|1950 BE|1}}<br />1950 DX{{·}}{{mp|1951 KB|1}}<br />1954 DA{{·}}1961 AL<br />{{mp|1969 EV|1}}
 | pronounced      = 
 | named_after     = Pyatiletka<br />{{small|([Five-year plans of the USSR](/source/Five-year_plans_of_the_USSR))}}<ref name="springer" />
 | mp_category     = [main-belt](/source/main-belt){{·}}{{small|([inner](/source/Kirkwood_gap))}}<ref name="lcdb" />
 | orbit_ref       = <ref name="jpldata" />
 | epoch           = 4 September 2017 ([JD](/source/Julian_day) 2458000.5)
 | uncertainty     = 0
 | observation_arc = 63.18 yr (23,075 days)
 | aphelion        = 2.4729 [AU](/source/Astronomical_unit)
 | perihelion      = 2.3310 AU
 | semimajor       = 2.4019 AU
 | eccentricity    = 0.0295
 | period          = 3.72 [yr](/source/Julian_year_(astronomy)) (1,360 days)
 | mean_anomaly    = 197.74[°](/source/Degree_(angle))
 | mean_motion     = {{Deg2DMS|0.2648|sup=ms}} / day
 | inclination     = 7.8981°
 | asc_node        = 105.50°
 | arg_peri        = 236.47°
 | dimensions      = 10.75 km {{small|(calculated)}}<ref name="lcdb" /><br />{{val|11.00|0.83}} km<ref name="AKARI" /><br />{{val|11.084|0.101}} km<ref name="Masiero-2014" /><br />{{val|11.554|0.074}} km<ref name="WISE" />
 | rotation        = {{val|8.899|0.0053}} [h](/source/Hour)<ref name="Waszczak-2015" />
 | albedo          = {{val|0.1931|0.0198}}<ref name="WISE" /><br />0.20 {{small|(assumed)}}<ref name="lcdb" /><br />{{val|0.211|0.033}}<ref name="AKARI" /><br />{{val|0.224|0.023}}<ref name="Masiero-2014" />
 | spectral_type   = [S](/source/S-type_asteroid)<ref name="lcdb" />
 | abs_magnitude   = {{val|11.759|0.002}} {{small|(R)}}<ref name="Waszczak-2015" />{{·}}12.1<ref name="jpldata" /><ref name="AKARI" /><ref name="WISE" />{{·}}12.21<ref name="lcdb" />{{·}}{{val|12.40|0.29}}<ref name="Veres-2015" />
}}

'''2122 Pyatiletka''', provisional designation {{mp|1971 XB}}, is a stony [asteroid](/source/asteroid) from the inner regions of the [asteroid belt](/source/asteroid_belt), approximately 11 kilometers in diameter.

The asteroid was discovered on 14 December 1971 by Soviet astronomer [Tamara Smirnova](/source/Tamara_Smirnova) at the [Crimean Astrophysical Observatory](/source/Crimean_Astrophysical_Observatory) in Nauchnyj, on the Crimean peninsula.<ref name="MPC-Pyatiletka" /> It was named for "pyatiletka", the first [Five-Year Plan of the USSR](/source/Five-year_plans_of_the_Soviet_Union).<ref name="springer" />

== Orbit and classification ==

''Pyatiletka'' orbits the Sun in the [inner](/source/Kirkwood_gap) main-belt at a distance of 2.3–2.5&nbsp;[AU](/source/Astronomical_unit) once every 3 years and 9 months (1,360 days). Its orbit has an [eccentricity](/source/orbital_eccentricity) of 0.03 and an [inclination](/source/orbital_inclination) of 8[°](/source/Degree_(angle)) with respect to the [ecliptic](/source/ecliptic).<ref name="jpldata" />

It was first identified as {{mp|1950 BE|1}} at [Simeiz Observatory](/source/Simeiz_Observatory) in 1950. The body's [observation arc](/source/observation_arc) begins at [Lowell Observatory](/source/Lowell_Observatory) in 1961, when it was identified as {{mp|1961 AL}}, 10 years prior to its official discovery observation at Nauchnyj.<ref name="MPC-Pyatiletka" />

== Physical characteristics ==

''Pyatiletka'' has been characterized as a stony [S-type asteroid](/source/S-type_asteroid).<ref name="lcdb" />

=== Lightcurves ===

A fragmentary rotational [lightcurve](/source/lightcurve) of ''Pyatiletka'' was obtained from photometric observations at the [Palomar Transient Factory](/source/Palomar_Transient_Factory) in California in February 2010. Lightcurve analysis gave a tentative [rotation period](/source/rotation_period) of 8.899 hours with a brightness variation of 0.10 [magnitude](/source/Magnitude_(astronomy)) ({{small|[U=1](/source/LCDB_quality_code)}}).<ref name="Waszczak-2015" /> As of 2017, no other lightcurve has been published.<ref name="lcdb" />

=== Diameter and albedo ===

According to the surveys carried out by the Japanese [Akari](/source/Akari_(satellite)) satellite and NASA's [Wide-field Infrared Survey Explorer](/source/Wide-field_Infrared_Survey_Explorer) with its subsequent [NEOWISE](/source/NEOWISE) mission, ''Pyatiletka'' measures between 11.00 and 11.55 kilometers in diameter, and its surface has an [albedo](/source/astronomical_albedo) between 0.1931 and 0.224.<ref name="AKARI" /><ref name="Masiero-2014" /><ref name="WISE" /> 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](/source/absolute_magnitude) of 12.21.<ref name="lcdb" />

== Naming ==

This [minor planet](/source/minor_planet) was named in honor of the [five-year plans of the Soviet Union](/source/five-year_plans_of_the_Soviet_Union) on the occasion of the 50th anniversary of its [first adoption](/source/First_five-year_plan_(Soviet_Union)).<ref name="springer" /> The official naming citation was published by the [Minor Planet Center](/source/Minor_Planet_Center) on 1 April 1980 ({{small|[M.P.C.](/source/Minor_Planet_Circulars) 5283}}).<ref name="MPC-Circulars-Archive" />

== References ==
{{reflist|30em|refs=

<ref name="jpldata">{{cite web
  |type       = 2017-04-30 last obs.
  |title      = JPL Small-Body Database Browser: 2122 Pyatiletka (1971 XB)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002122
  |publisher  = [Jet Propulsion Laboratory](/source/Jet_Propulsion_Laboratory)
  |accessdate = 11 June 2017}}</ref>

<ref name="springer">{{cite book
  |title      = Dictionary of Minor Planet Names – (2122) Pyatiletka
  |last       = Schmadel | first = Lutz D.
  |publisher  = [Springer Berlin Heidelberg](/source/Springer_Berlin_Heidelberg)
  |page       = 172
  |date       = 2007
  |isbn       = 978-3-540-00238-3
  |doi       = 10.1007/978-3-540-29925-7_2123 |chapter       = (2122) Pyatiletka }}</ref>

<ref name="MPC-Pyatiletka">{{cite web
  |title      = 2122 Pyatiletka (1971 XB)
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=2122
  |accessdate = 27 March 2017}}</ref>

<ref name="MPC-Circulars-Archive">{{cite web
  |title      = MPC/MPO/MPS Archive
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
  |accessdate = 27 March 2017}}</ref>

<ref name="Masiero-2014">{{cite journal
  |display-authors = 6
  |first1     = Joseph R. |last1 = Masiero
  |first2     = T. |last2 = Grav
  |first3     = A. K. |last3 = Mainzer
  |first4     = C. R. |last4 = Nugent
  |first5     = J. M. |last5 = Bauer
  |first6     = R. |last6 = Stevenson
  |first7     = S. |last7 = Sonnett
  |date       = August 2014
  |title      = Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos
  |url        = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014ApJ...791..121M
  |journal    = The Astrophysical Journal
  |volume     = 791
  |issue      = 2
  |page       = 11
  |bibcode    = 2014ApJ...791..121M
  |doi        = 10.1088/0004-637X/791/2/121
  |arxiv      = 1406.6645
  |access-date= 27 March 2017}}</ref>

<ref name="lcdb">{{cite LCDB|number = 2122
  |accessdate = 27 March 2017}}</ref>

<ref name="WISE">{{cite journal
  |display-authors = 6
  |first1     = A. |last1 = Mainzer
  |first2     = T. |last2 = Grav
  |first3     = J. |last3 = Masiero
  |first4     = E. |last4 = Hand
  |first5     = J. |last5 = Bauer
  |first6     = D. |last6 = Tholen
  |first7     = R. S. |last7 = McMillan
  |first8     = T. |last8 = Spahr
  |first9     = R. M. |last9 = Cutri
  |first10    = E. |last10 = Wright
  |first11    = J. |last11 = Watkins
  |first12    = W. |last12 = Mo
  |first13    = C. |last13 = Maleszewski
  |date       = November 2011
  |title      = NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
  |journal    = The Astrophysical Journal
  |volume     = 741
  |issue      = 2
  |page       = 25
  |bibcode    = 2011ApJ...741...90M
  |doi        = 10.1088/0004-637X/741/2/90
  |arxiv      = 1109.6407}}</ref>

<ref name="AKARI">{{cite journal
  |display-authors = 6
  |first1     = Fumihiko |last1 = Usui
  |first2     = Daisuke |last2 = Kuroda
  |first3     = Thomas G. |last3 = Müller
  |first4     = Sunao |last4 = Hasegawa
  |first5     = Masateru |last5 = Ishiguro
  |first6     = Takafumi |last6 = Ootsubo
  |first7     = Daisuke |last7 = Ishihara
  |first8     = Hirokazu |last8 = Kataza
  |first9     = Satoshi |last9 = Takita
  |first10    = Shinki |last10 = Oyabu
  |first11    = Munetaka |last11 = Ueno
  |first12    = Hideo |last12 = Matsuhara
  |first13    = Takashi |last13 = Onaka
  |date       = October 2011
  |title      = Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey
  |journal    = Publications of the Astronomical Society of Japan
  |volume     = 63
  |issue      = 5
  |pages      = 1117–1138
  |bibcode    = 2011PASJ...63.1117U
  |doi        = 10.1093/pasj/63.5.1117
  |doi-access= free
  }} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=2122 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])</ref>

<ref name="Waszczak-2015">{{cite journal
  |display-authors = 6
  |first1     = Adam |last1 = Waszczak
  |first2     = Chan-Kao |last2 = Chang
  |first3     = Eran O. |last3 = Ofek
  |first4     = Russ |last4 = Laher
  |first5     = Frank |last5 = Masci
  |first6     = David |last6 = Levitan
  |first7     = Jason |last7 = Surace
  |first8     = Yu-Chi |last8 = Cheng
  |first9     = Wing-Huen |last9 = Ip
  |first10    = Daisuke |last10 = Kinoshita
  |first11    = George |last11 = Helou
  |first12    = Thomas A. |last12 = Prince
  |first13    = Shrinivas |last13 = Kulkarni
  |date       = September 2015
  |title      = Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry
  |url        = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015AJ....150...75W
  |journal    = The Astronomical Journal
  |volume     = 150
  |issue      = 3
  |page       = 35
  |bibcode    = 2015AJ....150...75W
  |doi        = 10.1088/0004-6256/150/3/75
  |arxiv      = 1504.04041
  |access-date= 27 March 2017}}</ref>

<ref name="Veres-2015">{{cite journal
  |display-authors = 6
  |first1     = Peter |last1 = Veres
  |first2     = Robert |last2 = Jedicke
  |first3     = Alan |last3 = Fitzsimmons
  |first4     = Larry |last4 = Denneau
  |first5     = Mikael |last5 = Granvik
  |first6     = Bryce |last6 = Bolin
  |first7     = Serge |last7 = Chastel
  |first8     = Richard J. |last8 = Wainscoat
  |first9     = William S. |last9 = Burgett
  |first10    = Kenneth C. |last10 = Chambers
  |first11    = Heather |last11 = Flewelling
  |first12    = Nick |last12 = Kaiser
  |first13    = Eugen A. |last13 = Magnier
  |first14    = Jeff S. |last14 = Morgan
  |first15    = Paul A. |last15 = Price
  |first16    = John L. |last16 = Tonry
  |first17    = Christopher |last17 = Waters
  |date       = November 2015
  |title      = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results
  |url        = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V
  |journal    = Icarus
  |volume     = 261
  |pages      = 34–47
  |bibcode    = 2015Icar..261...34V
  |doi        = 10.1016/j.icarus.2015.08.007
  |arxiv      = 1506.00762
  |access-date= 27 March 2017}}</ref>

}} <!-- end of reflist -->

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{{DEFAULTSORT:Pyatiletka}}
002122
Category:Discoveries by Tamara Mikhaylovna Smirnova
Category:Named minor planets
19711214

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Adapted from the Wikipedia article [2122 Pyatiletka](https://en.wikipedia.org/wiki/2122_Pyatiletka) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/2122_Pyatiletka?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.