(23478) Chikumagawa Main-belt Asteroid
Discovered on 21 January 1991 by T. Seki at Geisei.
The Chikumagawa River originates in Nagano prefecture and flows through Niigata prefecture with many historic sites lying along it. “Chikumagawa Ryojo no Uta” (“A poem of a journey along the River Chikuma”) is a widely-known poem written by the prominent Japanese novelist and poet Shimazaki Toson.Naming citation (WGSBN Bull. 3, #14, 7), IAU / Minor Planet Center, via NASA/JPL
Where Chikumagawa is today
Seen from above the solar system on 2026-10-14: Chikumagawa is 3.15 au from the Sun and 3.38 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 23478 |
| Provisional designation | 1991 BZ |
| Orbit class | Main-belt Asteroid |
| Diameter | 7.87 km (#6,709 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.114 |
| Rotation period | 133 hours |
| Absolute magnitude (H) | 13.8 |
| Orbital period | 4.71 years |
| Semi-major axis | 2.81 au |
| Perihelion – aphelion | 2.13 – 3.49 au |
| Eccentricity | 0.244 |
| Inclination | 6.02° |
| Closest distance between its orbit and Earth's (MOID) | 1.14 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.