7472 Kumakiri

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7472 Kumakiri
Discovery[1]
Discovered byMakio Akiyama and Toshimasa Furuta
Discovery siteMishima Observatory
Discovery date13 February 1992
Designations
Named after
Kazuo Kumakiri
1969 VC2 · 1990 WG3 · 1992 CU
Main belt
Orbital characteristics[2]
Epoch 21 November 2025 (JD 2461000.5)
Uncertainty parameter 0
Aphelion3.3411 AU
Perihelion2.6780 AU
3.0095 AU
Eccentricity0.1102
5.2210 y (1906.98 d)
156.985°
0.1888° / d
Inclination9.916°
83.356°
82.320°
Jupiter MOID1.744 AU
TJupiter3.218
Physical characteristics
10.008±0.343 km (estimated)[2]
0.279±0.039 (estimated)[2]
Unknown/undetermined[3]: 3 
12.38[2]

7472 Kumakiri (provisional designation 1992 CU) is an asteroid from the outer main asteroid belt. It was discovered on 13 February 1992 by astronomers Makio Akiyama and Toshimasa Furuta at Mishima Observatory in Japan. Spectral observations of the asteroid show that it is basaltic in composition, possibly originating from a destroyed, differentiated planetesimal from the Solar System's early history. Its spectral classification is ambiguous, showing characteristics intermediate of multiple asteroid spectral types.

History

Kumakiri was briefly spotted on 15 November 1969 by the Crimean Astrophysical Observatory. Decades later, on 18–19 November 1990, it was observed by La Silla Observatory.[1] Thought to be separate objects, it was assigned a provisional designation each time (1969 VC2 and 1990 WG3).[4] It was sighted again on 13 February 1992 by astronomers Makio Akiyama and Toshimasa Furuta,[5] who were observing from Mishima Observatory in Susono, Japan.[1] The asteroid was given another designation 1992 CU, and in 1997 it was given the minor planet number of 7472 by the Minor Planet Center (MPC), with Akiyama and Furuta assigned as its discoverers.[6] It was named by the MPC on 2 February 1999 after Kazuo Kumakiri, an amateur astronomer local to Susono.[5]

Orbit

Kumakiri follows a stable[a] elliptical orbit around the Sun with an average distance (semi-major axis) of 3.34 astronomical units (AU),[2] inside the outer main asteroid belt.[7]: 230  Its semi-major axis places it near the 7:3 mean-motion resonance with Jupiter.[3]: 9  It is not a member of any known asteroid family.[7]: 233 

Kumakiri takes 5.22 Earth years to complete one orbit. Along its orbit, its distance from the Sun ranges from 2.68 AU at perihelion to 3.34 AU at aphelion due to its orbital eccentricity of 0.11. Its orbit is inclined by 9.9° with respect to the ecliptic.[2]

Physical characteristics

Kumakiri's size, estimated using thermal observations from NEOWISE, is about 10 kilometres (6.2 mi).[2]

Kumakiri's basaltic composition was first suggested by astronomers Fernando Roig and Ricardo Gil-Hutton in 2006 after searching for such asteroids using data from the Sloan Digital Sky Survey.[8]: 416, 417  A later study by Roig and R. Duffard in 2009 confirmed its basaltic nature based on its visible spectrum.[7]: 233  Basaltic asteroids are thought to form in the mantle of planetesimals from the ancient Solar System.[9]: 61  Nearly all known basaltic asteroids are located in the inner main belt within 2.5 AU as members of the prolific Vesta family, associated with the disrupted giant asteroid 4 Vesta.[7]: 229 [9]: 61  Kumakiri is too distant and spectrally distinct to be related to the Vesta family,[9]: 61  implying that it may be a fragment of a different, now destroyed or ejected planetesimal.[3]: 9 

Kumakiri is a spectral outlier without a clear spectral classification, with characteristics between the V, R, and O-type asteroids.[3]: 2–3  Roig and Duffard initially identified it as a V-type asteroid.[7]: 233  However, its fit for a V-type spectrum was poor, with a comparatively much shallower 2-μm band. Later researchers instead suggested an O-type classification with characteristics similar to—but not matching—that of O-type asteroid 3628 Božněmcová.[9]: 69 [10]: 21 [11]

See also

Notes

  1. Per a 50 Myr dynamical simulation.[7]: 233 

References

  1. "(7472) Kumakiri = 1969 VC2 = 1992 CU = 1990 WG3". Minor Planet Center. Retrieved 25 April 2026. (6388 obs)
  2. "JPL Small-Body Database Lookup: 7472 Kumakiri (1992 CU)" (2025-11-05 last obs.). Jet Propulsion Laboratory. Retrieved 25 April 2026.
  3. Galinier, M.; Avdellidou, C.; Delbo, M.; Galluccio, L. (July 2026). "New insights into Erg Chech 002 analogues in the main belt from near-infrared spectroscopy". Icarus. 453 117050. arXiv:2603.24332. doi:10.1016/j.icarus.2026.117050.
  4. "M. P. C. 17583" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 30 January 1991. p. 111. Retrieved 26 April 2026.
  5. "M. P. C. 33788" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 2 February 1999. p. 174. Retrieved 26 April 2026.
  6. "M. P. C. 29082" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 22 February 1997. p. 174. Retrieved 26 April 2026.
  7. Duffard, R.; Roig, F. (February 2009). "Two new V-type asteroids in the outer Main Belt?". Planetary and Space Science. 57 (2): 229–234. doi:10.1016/j.pss.2008.07.009.
  8. Roig, F.; Gil-Hutton, R. (August 2006). "Selecting candidate V-type asteroids from the analysis of the Sloan Digital Sky Survey colors". Icarus. 183 (2): 411–419. doi:10.1016/j.icarus.2006.04.002.
  9. Leith, Thomas B.; Moskovitz, Nicholas A.; Mayne, Rhiannon G.; DeMeo, Francesca E.; Takir, Driss; Burt, Brian J.; Binzel, Richard P.; Pefkou, Dimitra (October 2017). "The compositional diversity of non-Vesta basaltic asteroids". Icarus. 295: 61–73. arXiv:1705.06304. doi:10.1016/j.icarus.2017.05.007.
  10. Mahlke, M.; Carry, B.; Mattei, P.-A. (September 2022). "Asteroid taxonomy from cluster analysis of spectrometry and albedo". Astronomy & Astrophysics. 665. arXiv:2203.11229. doi:10.1051/0004-6361/202243587. A26.
  11. Burbine, T. H.; Duffard, R.; Buchanan, P. C.; Cloutis, E. A.; Binzel, R. P. (March 2011). "Spectroscopy of O-Type Asteroids". 42nd Annual Lunar and Planetary Science Conference (1608): 2483.