(21254) Jonan Main-belt Asteroid
Discovered on 24 January 1996 by J. Kobayashi at Kumamoto.
Jonan is the town where the Kumamoto Civil Astronomical Observatory is located. The naming of the minor planet on the observatory's twentieth anniversary acknowledges the wonderful support of the townspeople.Naming citation (20020427/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Jonan is today
Seen from above the solar system on 2026-10-14: Jonan is 2.52 au from the Sun and 2.87 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21254 |
| Provisional designation | 1996 BG2 |
| Orbit class | Main-belt Asteroid |
| Diameter | 5.98 km (#8,958 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.375 |
| Absolute magnitude (H) | 13.4 |
| Orbital period | 4.37 years |
| Semi-major axis | 2.67 au |
| Perihelion – aphelion | 2.51 – 2.83 au |
| Eccentricity | 0.0593 |
| Inclination | 21.5° |
| Closest distance between its orbit and Earth's (MOID) | 1.56 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.