Astronomy:1430 Somalia

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1430 Somalia
001430-asteroid shape model (1430) Somalia.png
Modelled shape of Somalia from its lightcurve
Discovery[1]
Discovered byC. Jackson
Discovery siteJohannesburg Obs.
Discovery date5 July 1937
Designations
(1430) Somalia
Named afterSomalia[2] (African country)
1937 NK · 1929 RQ
1954 UR1 · 1957 HT
1962 VF
Minor planet categorymain-belt · (middle)
background[3] · Astraea[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc79.73 yr (29,122 days)
|{{{apsis}}}|helion}}3.0674 AU
|{{{apsis}}}|helion}}2.0508 AU
2.5591 AU
Eccentricity0.1986
Orbital period4.09 yr (1,495 days)
Mean anomaly184.53°
Mean motion0° 14m 26.88s / day
Inclination3.2883°
Longitude of ascending node327.25°
351.42°
Physical characteristics
Dimensions8.77±1.58 km[5]
9.352±0.133 km[6]
9.44±0.36 km[7]
9.674±0.089 km[8]
10.79 km (calculated)[9]
Rotation period6.90907±0.00005 h[10]
6.910±0.001 h[11]
6.913±0.001 h[12]
Geometric albedo0.1436±0.0287[8]
0.153±0.032[6]
0.162±0.014[7]
0.20 (assumed)[9]
0.31±0.14[5]
S (assumed)[9]
Absolute magnitude (H)12.1[1] · 12.2[9] · 12.35±0.35[13] · 12.41[5] · 12.80[7][8]


1430 Somalia, provisional designation 1937 NK, is a stony background asteroid from the central regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 5 July 1937, by astronomer Cyril Jackson at the Union Observatory in Johannesburg.[14] It was named for the African country of Somalia.[2]

Orbit and classification

Based on the hierarchical clustering method, Somalia is a non-family asteroid of the main belt's background population (Nesvorný),[3] as well as a core member of the Astraea family (Milani and Knežević).[4] It orbits the Sun in the central asteroid belt at a distance of 2.1–3.1 AU once every 4 years and 1 month (1,495 days). Its orbit has an eccentricity of 0.20 and an inclination of 3° with respect to the ecliptic.[1]

The asteroid was first identified as 1929 RQ at Simeiz or Lowell observatories in September 1929. The body's observation arc begins with its official discovery observation at Johannesburg in 1937.[14]

Physical characteristics

Somalia is an assumed stony S-type asteroid.[9]

Lightcurves

In 2011, two rotational lightcurves of Somalia were obtained from photometric observations by French amateur astronomer René Roy, and by astronomers at the Bassano Bresciano Observatory (565) in Italy. Lightcurve analysis gave a rotation period of 6.910 and 6.913 hours with a brightness amplitude of 0.40 and 0.45 magnitude, respectively ({{{1}}}).[11][12]

In 2016, a modeled lightcurve was derived from various photometric database sources, giving a concurring sidereal period of 6.90907 hours. The modelled lightcurve also determined two spin axis of (297.0°, 42.0°) and (128.0°, 47.0°) in ecliptic coordinates.[10]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Somalia measures between 8.77 and 9.674 kilometers in diameter and its surface has an albedo between 0.1436 and 0.31.[5][6][7][8]

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 10.79 kilometers based on an absolute magnitude of 12.2.[9]

Naming

This minor planet was named after the country of Somalia, located in the Horn of Africa.[2] The official naming citation was published by the Minor Planet Center on 1 February 1980 (M.P.C. 5181).[15]

References

  1. ↑ 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 1430 Somalia (1937 NK)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001430. 
  2. ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(1430) Somalia". Dictionary of Minor Planet Names – (1430) Somalia. Springer Berlin Heidelberg. p. 115. doi:10.1007/978-3-540-29925-7_1431. ISBN 978-3-540-00238-3. 
  3. ↑ 3.0 3.1 "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. https://sbntools.psi.edu/ferret/PropertySearch/familyForm.action. 
  4. ↑ 4.0 4.1 "Asteroid 1430 Somalia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=1430. 
  5. ↑ 5.0 5.1 5.2 5.3 Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T. et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal 152 (3): 12. doi:10.3847/0004-6256/152/3/63. Bibcode: 2016AJ....152...63N. 
  6. ↑ 6.0 6.1 6.2 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J. et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal 741 (2): 20. doi:10.1088/0004-637X/741/2/68. Bibcode: 2011ApJ...741...68M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M. Retrieved 26 October 2017. 
  7. ↑ 7.0 7.1 7.2 7.3 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. doi:10.1093/pasj/63.5.1117. Bibcode: 2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  8. ↑ 8.0 8.1 8.2 8.3 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. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 "LCDB Data for (1430) Somalia". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1430%7CSomalia. 
  10. ↑ 10.0 10.1 Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M. et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics 586: 24. doi:10.1051/0004-6361/201527441. Bibcode: 2016A&A...586A.108H. 
  11. ↑ 11.0 11.1 Behrend, Raoul. "Asteroids and comets rotation curves – (1430) Somalia". Geneva Observatory. http://obswww.unige.ch/~behrend/page4cou.html#001430. 
  12. ↑ 12.0 12.1 Strabla, Luca; Quadri, Ulisse; Girelli, Roberto (July 2012). "Lightcurve Analysis for Eight Minor Palnets at Bassano Bresciano Observatory". The Minor Planet Bulletin 39 (3): 177–179. ISSN 1052-8091. Bibcode: 2012MPBu...39..177S. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012MPBu...39..177S. Retrieved 26 October 2017. 
  13. ↑ 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. doi:10.1016/j.icarus.2015.08.007. Bibcode: 2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 26 October 2017. 
  14. ↑ 14.0 14.1 "1430 Somalia (1937 NK)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=1430. 
  15. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. 

External links



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