astro.wikisort.org - Asteroid

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]

9844 Otani

Discovery [1]
Discovered by	Y. Kushida O. Muramatsu
Discovery site	Yatsugatake South Base Obs.
Discovery date	23 November 1989
Designations
MPC designation	(9844) Otani
Named after	Toyokazu Otani (astronomy lecturer)[2]
Alternative designations	1989 WF1 · 1980 VF1 1996 HA26
Minor planet category	main-belt · Eunomia [3]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	67.44 yr (24,634 days)
Aphelion	3.2894 AU
Perihelion	2.1105 AU
Semi-major axis	2.7000 AU
Eccentricity	0.2183
Orbital period (sidereal)	4.44 yr (1,620 days)
Mean anomaly	102.78°
Mean motion	0° 13m 19.92s / day
Inclination	12.932°
Longitude of ascending node	60.733°
Argument of perihelion	353.14°
Physical characteristics
Dimensions	3.84 km (calculated)[3]
Synodic rotation period	10.0730±0.0053 h[4]
Geometric albedo	0.21 (assumed)[3]
Spectral type	S [3]
Absolute magnitude (H)	13.87±0.47[5] · 13.9[1] · 13.939±0.004 (R)[4] · 14.39[3]

Orbit and classification

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

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]

Naming

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]

References

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
• 9844 Otani at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 9844 Otani at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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