(18289) Yokoyamakoichi Main-belt Asteroid
Discovered on 22 October 1976 by Kosai, H., Hurukawa, K. at Kiso.
Koichi Yokoyama (b. 1940) is a professor emeritus of the National Astronomical observatory, Japan. He was Director of the International Polar Motion Service (1981-1987) and first chairman of the directing board of the International Earth Rotation Service. He also improved the nutation tables.Naming citation (MPC batch dated 2017-01-12), IAU / Minor Planet Center, via NASA/JPL
Where Yokoyamakoichi is today
Seen from above the solar system on 2026-10-14: Yokoyamakoichi is 3.06 au from the Sun and 4.05 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 18289 |
| Provisional designation | 1976 UB16 |
| Orbit class | Main-belt Asteroid |
| Rotation period | 34.0 hours |
| Absolute magnitude (H) | 13.91 |
| Orbital period | 4.71 years |
| Semi-major axis | 2.81 au |
| Perihelion – aphelion | 2.30 – 3.32 au |
| Eccentricity | 0.182 |
| Inclination | 12.2° |
| Closest distance between its orbit and Earth's (MOID) | 1.32 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also discovered on 22 October 1976
- (2271) Kiso
- (2337) Boubin
- (2340) Hathor
- (2470) Agematsu
- (2989) Imago
- (5541) Seimei
- (6846) Kansazan
- (10006) Sessai
- (11442) Seijin-Sanso
- (14313) Dodaira
- (16357) Risanpei