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词条 1246 Chaka
释义

  1. Orbit and classification

  2. Naming

  3. Physical characteristics

      Rotation period    Diameter and albedo  

  4. Notes

  5. References

  6. External links

{{Infobox planet
| minorplanet = yes
| name = 1246 Chaka
| background = #D6D6D6
| image =
| image_size =
| caption =
| discovery_ref =  [1]
| discoverer = C. Jackson
| discovery_site = Johannesburg Obs.
| discovered = 23 July 1932
| mpc_name = (1246) Chaka
| alt_names = 1932 OA
| pronounced =
| named_after = {{nowrap|Shaka {{small|(King of the Zulus)}}[2]}}
| mp_category = main-belt [1]{{·}}{{small|(middle)}}
background [5][6]
| orbit_ref =  
| epoch = 27 April 2019 (JD 2458600.5)
| uncertainty = 0
| observation_arc = 86.29 yr (31,519 d)
| aphelion = 3.4329 AU
| perihelion = 1.8068 AU
| semimajor = 2.6198 AU
| eccentricity = 0.3103
| period = 4.24 yr (1,549 d)
| mean_anomaly = 128.91°
| mean_motion = {{Deg2DMS|0.2324|sup=ms}} / day
| inclination = 16.004°
| asc_node = 290.52°
| arg_peri = 54.847°
| mean_diameter = {{val|17.634|0.498|ul=km}}[8][9]
{{val|17.73|3.89|u=km}}[10]
{{val|18.11|0.9|u=km}}[11]
{{val|19.596|0.035|u=km}}[12]
{{val|20.84|1.39|u=km}}[13]
| rotation = {{val|25.462|0.001|ul=h}}{{efn|name=lcdb-Garlitz-2013}}
| albedo = {{val|0.195}}[13]
{{val|0.2045}}[12]
{{val|0.2351}}[11]
{{val|0.26}}[10]
{{val|0.310}}[8]
| spectral_type = A {{small|(S3OS2-TH)}}[19]
Sl {{small|(S3OS2-BB)}}[19]
| abs_magnitude = 10.8[10][13]
10.9[1][8][11][12]
}}1246 Chaka, provisional designation {{mp|1932 OA}}, is a background asteroid from the central regions of the asteroid belt, approximately {{convert|18|km|mi|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered on 23 July 1932, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg.[1] The uncommon A/Sl-type asteroid has a longer than average rotation period of 25.5 hours.[29] It was named for the Zulu King Shaka.[2]

Orbit and classification

Chaka is a non-family asteroid from the main belt's background population.[5][6] It orbits the Sun in the central asteroid belt at a distance of 1.8–3.4 AU once every 4 years and 3 months (1,549 days; semi-major axis of 2.62 AU). Its orbit has an eccentricity of 0.31 and an inclination of 16° with respect to the ecliptic. The body's observation arc begins with its first observation at Johannesburg on 4 July 1932, three weeks prior to its official discovery observation.[1]

Naming

This minor planet was named after Shaka (c. 1787–1828), also Chaka or Tchaka, founder and one of the most influential monarchs of the Zulu Kingdom. The official {{MoMP|1246|naming citation}} was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ({{small|H 115}}).[2]

Physical characteristics

Chaka{{'s}} spectral type has been determined during the Small Solar System Objects Spectroscopic Survey (S3OS2). In the Tholen-like taxonomic variant of the survey, the asteroid is a rare A-type, while in the SMASS-like variant it is a Sl-subtype, that transitions between the common S- and uncommon L-type asteroids.[5][19]

Rotation period

In October 2013, a rotational lightcurve of Chaka was obtained from photometric observations by Joe Garlitz at his Elgin Observatory. Lightcurve analysis gave a well-defined rotation period of {{val|25.462|0.001}} hours with a brightness amplitude of 0.18 magnitude ({{small|U=3}}).{{efn|name=lcdb-Garlitz-2013}} Other period determinations were made by European astronomers (20 h; Δ0.2) at OHP and La Silla in October 1996 ({{small|U=2}}),[38] and by Andrea Ferrero (25.44 h; Δ0.25) at the Italian Bigmuskie Observatory {{Obscode|B88}} in November 2013 ({{small|U=2}}).[39]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Chaka measures between 17.63 and 20.84 kilometers in diameter and its surface has an albedo between 0.195 and 0.310.[8][9][10][11][12][13] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.2351 and a diameter of 18.11 kilometers based on an absolute magnitude of 10.9.[29]

Notes

{{notelist|refs={{efn|name=lcdb-Garlitz-2013|1=Joe Garlitz (2013; web) observations of (1246) Chaka at the Elgin Observatory from October 2013. Posted data on the web site of the Collaborative Asteroid Lightcurve Link. Results: rotation period of {{val|25.462|0.001}} hours with a brightness amplitude of {{val|0.18|0.02}} mag. Quality code is 3. Summary figures at the LCDB. Also see [https://users.eoni.com/~garlitzj/Period.htm Observers homepage].}}

}}

References

1. ^1 2 3 {{cite book |title = Dictionary of Minor Planet Names – (1246) Chaka |last = Schmadel | first = Lutz D. |publisher = Springer Berlin Heidelberg |page = 115 |date = 2007 |isbn = 978-3-540-00238-3 |doi = 10.1007/978-3-540-29925-7_1247 |chapter = (1246) Chaka }}
2. ^1 2 3 4 5 {{cite web |title = 1246 Chaka (1932 OA) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=1246 |accessdate = 14 December 2018}}
3. ^1 2 3 {{Cite journal |first1 = D. |last1 = Lazzaro |first2 = C. A. |last2 = Angeli |first3 = J. M. |last3 = Carvano |first4 = T. |last4 = Mothé-Diniz |first5 = R. |last5 = Duffard |first6 = M. |last6 = Florczak |date = November 2004 |title = S3OS2: the visible spectroscopic survey of 820 asteroids |url = http://sirrah.troja.mff.cuni.cz/yarko-site/tmp/eos/NEW/spectral_type_figure/s3os2.pdf |journal = Icarus |volume = 172 |issue = 1 |pages = 179–220 |bibcode = 2004Icar..172..179L |doi = 10.1016/j.icarus.2004.06.006 |access-date= 14 December 2018}}
4. ^1 2 {{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 |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 }}
5. ^1 2 {{cite web |title = Asteroid (1246) Chaka |publisher = AstDyS-2, Asteroids – Dynamic Site |url = http://hamilton.dm.unipi.it/astdys/index.php?n=1246&pc=1.1.6 |accessdate = 14 December 2018}}
6. ^1 2 3 {{cite web |title = Asteroid 1246 Chaka |work = Small Bodies Data Ferret |url = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=1246+Chaka |accessdate = 14 December 2018}}
7. ^1 2 {{cite web |title = LCDB Data for (1246) Chaka |publisher = Asteroid Lightcurve Database (LCDB) |url = http://www.minorplanet.info/PHP/GenerateALCDEFPage_Local.php?AstInfo=1246%7CChaka |accessdate = 14 December 2018}}
8. ^1 2 3 4 {{cite journal |display-authors = 6 |first1 = Joseph R. |last1 = Masiero |first2 = A. K. |last2 = Mainzer |first3 = T. |last3 = Grav |first4 = J. M. |last4 = Bauer |first5 = R. M. |last5 = Cutri |first6 = C. |last6 = Nugent |first7 = M. S. |last7 = Cabrera |date = November 2012 |title = Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids |journal = The Astrophysical Journal Letters |volume = 759 |issue = 1 |page = 5 |bibcode = 2012ApJ...759L...8M |doi = 10.1088/2041-8205/759/1/L8 |arxiv = 1209.5794 }}
9. ^1 2 3 4 {{cite journal |display-authors = 6 |first1 = C. R. |last1 = Nugent |first2 = A. |last2 = Mainzer |first3 = J. |last3 = Masiero |first4 = J. |last4 = Bauer |first5 = R. M. |last5 = Cutri |first6 = T. |last6 = Grav |first7 = E. |last7 = Kramer |first8 = S. |last8 = Sonnett |first9 = R. |last9 = Stevenson |first10 = E. L. |last10 = Wright |date = December 2015 |title = NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos |journal = The Astrophysical Journal |volume = 814 |issue = 2 |page = 13 |bibcode = 2015ApJ...814..117N |doi = 10.1088/0004-637X/814/2/117 |arxiv = 1509.02522 }}
10. ^1 2 3 4 {{cite journal |display-authors = 6 |first1 = A. K. |last1 = Mainzer |first2 = J. M. |last2 = Bauer |first3 = R. M. |last3 = Cutri |first4 = T. |last4 = Grav |first5 = E. A. |last5 = Kramer |first6 = J. R. |last6 = Masiero |first7 = C. R. |last7 = Nugent |first8 = S. M. |last8 = Sonnett |first9 = R. A. |last9 = Stevenson |first10 = E. L. |last10 = Wright |date = June 2016 |title = NEOWISE Diameters and Albedos V1.0 |url = https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_COMPIL_5_NEOWISEDIAM_V1_0/data/neowise_mainbelt.tab |journal = NASA Planetary Data System |pages = EAR–A–COMPIL–5–NEOWISEDIAM–V1.0 |bibcode = 2016PDSS..247.....M |access-date= 14 December 2018}}
11. ^1 2 3 4 {{cite journal |first1 = E. F. |last1 = Tedesco |first2 = P. V. |last2 = Noah |first3 = M. |last3 = Noah |first4 = S. D. |last4 = Price |date = October 2004 |title = IRAS Minor Planet Survey V6.0 |url = https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab |journal = NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0 |pages = IRAS–A–FPA–3–RDR–IMPS–V6.0 |bibcode = 2004PDSS...12.....T |access-date= 14 December 2018}}
12. ^1 2 3 4 {{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 }} (catalog)
13. ^1 {{Cite journal |display-authors = 6 |first1 = M. |last1 = Florczak |first2 = E. |last2 = Dotto |first3 = M. A. |last3 = Barucci |first4 = M. |last4 = Birlan |first5 = A. |last5 = Erikson |first6 = M. |last6 = Fulchignoni |first7 = A. |last7 = Nathues |first8 = L. |last8 = Perret |first9 = P. |last9 = Thebault |date = November 1997 |title = Rotational properties of main belt asteroids: photoelectric and CCD observations of 15 objects |journal = Planetary and Space Science |volume = 45 |issue = 11 |pages = 1423–1435 |bibcode = 1997P&SS...45.1423F |doi = 10.1016/S0032-0633(97)00121-9 }}
14. ^1 {{Cite journal |author = Ferrero, Andrea |date = July 2014 |title = Period Determination of Six Main Belt Asteroids |journal = The Minor Planet Bulletin |volume = 41 |issue = 3 |pages = 184–185 |issn = 1052-8091 |bibcode = 2014MPBu...41..184F }}
[1][2][3][4][5][6][7][8][9][10][11][12][13][14]

}}

External links

  • [https://users.eoni.com/~garlitzj/index.html Elgin Observatory], Backyard Amateur Astromomy
  • Asteroid Lightcurve Database (LCDB), query form (info)
  • [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
  • [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
  • {{AstDys|1246}}
  • {{JPL small body}}
{{Use dmy dates|date=December 2018}}{{Minor planets navigator |1245 Calvinia |number=1246 |1247 Memoria}}{{Small Solar System bodies}}{{DEFAULTSORT:Chaka}}

5 : Background asteroids|Discoveries by Cyril V. Jackson|Minor planets named for people|Named minor planets|Astronomical objects discovered in 1932
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