9844 Otani

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9844 Otani
Discovery [1]
Discovered by Y. Kushida
O. Muramatsu
Discovery site Yatsugatake South Base Observatory
Discovery date 23 November 1989
MPC designation 9844 Otani
Named after
Toyokazu Otani
(astronomy lecturer)[2]
1989 WF1 · 1980 VF1
1996 HA26
main-belt · Eunomia[3]
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 65.97 yr (24,097 days)
Aphelion 3.2888 AU
Perihelion 2.1093 AU
2.6990 AU
Eccentricity 0.2185
4.43 yr (1,620 days)
0° 13m 20.28s / day
Inclination 12.931°
Physical characteristics
Dimensions 3.84 km (calculated)[3]
10.0730±0.0053 h[4]
0.21 (assumed)[3]
13.939±0.004 (R)[4]

9844 Otani, provisional designation 1989 WF1, is a stony Eunomian asteroid from the middle region of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 23 November 1989, by Japanese astronomers Yoshio Kushida and Osamu Muramatsu at the Yatsugatake South Base Observatory, Hokuto, near the Greater Tokyo Area, Japan.[6]

The asteroid is a member of the Eunomia family, a large group of S-type asteroids and the most prominent family in the intermediate main-belt. It orbits the Sun at a distance of 2.1–3.3 AU once every 4 years and 5 months (1,620 days). Its orbit has an eccentricity of 0.22 and an inclination of 13° with respect to the ecliptic.[1] The first precovery was taken at Palomar Mountain in 1949, extending the asteroid's observation arc by 40 years prior to its discovery.[6]

A rotational light-curve for this asteroid was obtained from photometric observations at the Palomar Transient Factory in February 2013. It gave a rotation period of 10.073±0.0053 hours with a brightness variation of 0.18 in magnitude (U=2).[4] The Collaborative Asteroid Lightcurve Link assumes an albedo 0.21 – derived from 15 Eunomia, the family's largest member and namesake – and calculates a diameter of 3.84 kilometers, based on an absolute magnitude of 14.39.[3]

The minor planet was named in honor of Toyokazu Otani (b. 1928), a renowned observer of minor planets, lecturer at the Gotoh Planetarium, and long-time employee at the Astronomical Museum in Tokyo (1956–1988).[2] Naming citation was published on 2 April 1999 (M.P.C. 34355).[7]


  1. ^ a b c d "JPL Small-Body Database Browser: 9844 Otani (1989 WF1)" (2015-11-10 last obs.). Jet Propulsion Laboratory. Retrieved 1 August 2016. 
  2. ^ a b Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (9844) Otani. Springer Berlin Heidelberg. p. 711. ISBN 978-3-540-00238-3. Retrieved 1 August 2016. 
  3. ^ a b c d e f "LCDB Data for (9844) Otani". Asteroid Lightcurve Database (LCDB). Retrieved 1 August 2016. 
  4. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041free to read. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 1 January 2016. 
  5. ^ 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:1506.00762free to read. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 1 August 2016. 
  6. ^ a b "9844 Otani (1989 WF1)". Minor Planet Center. Retrieved 1 August 2016. 
  7. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 1 August 2016. 

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