9844 Otani

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9844 Otani
Discovery [1]
Discovered byY. Kushida
O. Muramatsu
Discovery siteYatsugatake South Base Obs.
Discovery date23 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 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc67.44 yr (24,634 days)
Aphelion3.2894 AU
Perihelion2.1105 AU
2.7000 AU
4.44 yr (1,620 days)
0° 13m 19.92s / day
Physical characteristics
Dimensions3.84 km (calculated)[3]
10.0730±0.0053 h[4]
0.21 (assumed)[3]
13.87±0.47[5] · 13.9[1] · 13.939±0.004 (R)[4] · 14.39[3]

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] It was named for Japanese astronomer Toyokazu Otani.[2]

Orbit and classification[edit]

Otani 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 in the central main-belt 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 used observation was a precovery taken at Palomar Mountain in 1949, extending the body's observation arc by 40 years prior to its official discovery observation.[6]

Physical characteristics[edit]

A rotational lightcurve of Otani 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 with an absolute magnitude of 14.39.[3]


This minor planet was named in honor of Toyokazu Otani (born 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] The official naming citation was published by the Minor Planet Center on 2 April 1999 (M.P.C. 34355).[7]


  1. ^ a b c d "JPL Small-Body Database Browser: 9844 Otani (1989 WF1)" (2017-04-30 last obs.). Jet Propulsion Laboratory. Retrieved 22 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(9844) Otani". Dictionary of Minor Planet Names – (9844) Otani. Springer Berlin Heidelberg. p. 711. doi:10.1007/978-3-540-29925-7_7723. ISBN 978-3-540-00238-3.
  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:1504.04041. 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:1506.00762. 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.

External links[edit]