(129561) Chuhachi Main-belt Asteroid
Discovered on 9 February 1997 by A. Nakamura at Kuma Kogen.
In 1891 a self-taught aviation engineer, Chuhachi Ninomiya (1866-1936) became the first Japanese to fly a propeller-driven model aircraft. A manpowered aircraft, not completed in Ninomiya's time because of the lack of funds, was manufactured in 1991 following his design, and it flew 50 meters.Naming citation (20091004/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Chuhachi is today
Seen from above the solar system on 2026-10-14: Chuhachi is 2.42 au from the Sun and 3.41 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 129561 |
| Provisional designation | 1997 CS21 |
| Orbit class | Main-belt Asteroid |
| Diameter | 3.60 km (#13,725 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0380 |
| Absolute magnitude (H) | 16.43 |
| Orbital period | 4.15 years |
| Semi-major axis | 2.58 au |
| Perihelion – aphelion | 2.32 – 2.85 au |
| Eccentricity | 0.102 |
| Inclination | 2.24° |
| Closest distance between its orbit and Earth's (MOID) | 1.31 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.