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5481 Kiuchi, provisional designation 1990 CH, is a bright binary[4] Vestian asteroid from the inner regions of the asteroid belt, approximately 4 kilometers (2.5 miles) in diameter. It was discovered on 15 February 1990, by Japanese astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory on Hokkaidō, Japan, and named after their college Tsuruhiko Kiuchi.[2][9] The V-type asteroid has a rotation period of 3.6 hours.[5]

5481 Kiuchi
Discovery [1]
Discovered byK. Endate
K. Watanabe
Discovery siteKitami Obs.
Discovery date15 February 1990
MPC designation(5481) Kiuchi
Named after
Tsuruhiko Kiuchi
(Japanese amateur astronomer)[2]
1990 CH · 1970 SR
main-belt · Vesta[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc46.14 yr (16,851 days)
Aphelion2.4858 AU
Perihelion2.1936 AU
2.3397 AU
3.58 yr (1,307 days)
0° 16m 31.44s / day
Known satellites1 (Ds/Dp 0.33, P: 20.90 h)[4]
Physical characteristics
Mean diameter
3.86 km (calculated)[5]
3.6196±0.0002 h[4][6]
0.40 (assumed)[5]
12.98±0.1 (R)[4] · 13.4[1] · 13.676±0.062[5][8] · 13.73±0.29[7]

Family and orbitEdit

Kiuchi is a bright core member of the Vesta family,[3] one of the main-belt's largest families. It orbits the Sun in the inner main-belt at a distance of 2.2–2.5 AU once every 3 years and 7 months (1,307 days). Its orbit has an eccentricity of 0.06 and an inclination of 6° with respect to the ecliptic.[1] It was first identified as 1970 SR at Crimea–Nauchnij in 1970, extending the body's observation arc by 20 years prior to its official discovery observation at Kitami.[9]


This minor planet was named in honor of Japanese amateur astronomer and discoverer of comets, Tsuruhiko Kiuchi (born 1954), who is known for the recovery of the periodic Perseid Comet Swift–Tuttle, a previously lost comet (also see naming citations for (5035) Swift and (5036 Tuttle). Based on a prediction by Brian Marsden, Kiuchi made this recovery in 1992, only using binoculars.[2] The approved naming citation was published by the Minor Planet Center on 1 September 1993 (M.P.C. 22510).[10]

Binary asteroidEdit


In March 2008, a lightcurve of Kiuchi was obtained from photometric observations by astronomers Peter Kušnirák and Petr Pravec at Ondřejov Observatory in the Czech Republic, by Julian Oey at Leura Observatory, Australia, by Robert Stephens at Goat Mountain, California, by Mark Husárik at Skalnaté pleso Observatory, Slovakia, and by Judit Györgyey Ries at McDonald Observatory, Texas.

These photometric observations revealed, that a Kiuchi is a synchronous binary asteroid with a minor-planet moon orbiting it every 20.90 hours based on mutual eclipsing and occultation events. The satellite's diameter is about a third of that of Kiuchi, which translates into 1.3 kilometers (secondary-to-primary mean-diameter ratio of 0.33±0.02).[4]


According to the surveys carried out by PanSTARRS, Kiuchi is a bright V-type asteroid.[7] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.40 and calculates a diameter of 3.86 kilometers, using an absolute magnitude of 13.676 from Petr Pravec's revised WISE data.[5]

Kiuchi itself has a rotation period of 3.6196±0.0002 hours with a small brightness variation of 0.1 magnitude, indicating a nearly spheroidal shape (U=n.a.).[4] Photometric follow-up observations by Petr Pravec confirmed the results in 2013 and 2016, giving a period of 3.6198 and 3.6196 hours with an amplitude of 0.08 and 0.1 magnitude, and an orbital period for the satellite of 20.9 and 20.9062 hours, respectively (U=3/n.a.).[6][a]


  1. ^ Pravec (2013) web: rotation period 3.6198±0.0003 hours with a brightness amplitude of 0.08 mag. Summary figures for (5481) Kiuchi at Collaborative Asteroid Lightcurve Link (CALL)


  1. ^ a b c d "JPL Small-Body Database Browser: 5481 Kiuchi (1990 CH)" (2016-11-15 last obs.). Jet Propulsion Laboratory. Retrieved 4 July 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(5481) Kiuchi". Dictionary of Minor Planet Names – (5481) Kiuchi. Springer Berlin Heidelberg. p. 468. doi:10.1007/978-3-540-29925-7_5245. ISBN 978-3-540-00238-3.
  3. ^ a b "Asteroid (5481) Kiuchi – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 23 July 2018.
  4. ^ a b c d e f Kusnirak, P.; Pravec, P.; Oey, J.; Stephens, R.; Husarik, M.; Ries, J. (April 2008). "(5481) Kiuchi". Central Bureau Electronic Telegrams. 1339 (1339): 1. Bibcode:2008CBET.1339....1K. Retrieved 20 March 2017.
  5. ^ a b c d e f "LCDB Data for (5481) Kiuchi". Asteroid Lightcurve Database (LCDB). Retrieved 20 March 2017.
  6. ^ a b Pravec, P.; Scheirich, P.; Kusnirák, P.; Hornoch, K.; Galád, A.; Naidu, S. P.; et al. (March 2016). "Binary asteroid population. 3. Secondary rotations and elongations". Icarus. 267: 267–295. Bibcode:2016Icar..267..267P. doi:10.1016/j.icarus.2015.12.019. Retrieved 20 March 2017.
  7. ^ a b c 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 20 March 2017.
  8. ^ Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved 20 March 2017.
  9. ^ a b "5481 Kiuchi (1990 CH)". Minor Planet Center. Retrieved 20 March 2017.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 20 March 2017.

External linksEdit