(21089) Mochizuki Main-belt Asteroid
Discovered on 8 February 1992 by T. Seki at Geisei.
Seiji Mochizuki (b. 1942) was born in Tokyo and worked for an optical company from 1967 to 1979. The 0.6-m reflector at Geisei observatory was designed by him. Even now it is still used for astronomical observation.Naming citation (20040306/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Mochizuki is today
Seen from above the solar system on 2026-10-14: Mochizuki is 2.78 au from the Sun and 3.31 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21089 |
| Provisional designation | 1992 CQ |
| Orbit class | Main-belt Asteroid |
| Diameter | 7.67 km (#6,918 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.166 |
| Rotation period | 48.0 hours |
| Absolute magnitude (H) | 12.88 |
| Orbital period | 4.36 years |
| Semi-major axis | 2.67 au |
| Perihelion – aphelion | 2.32 – 3.02 au |
| Eccentricity | 0.132 |
| Inclination | 14.3° |
| Closest distance between its orbit and Earth's (MOID) | 1.34 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Seiji
All asteroids named after someone called Seiji