(10489) Keinonen Main-belt Asteroid
Discovered on 15 October 1985 by E. Bowell at Anderson Mesa.
Juhani Keinonen (b. 1946) is an emeritus professor and a long-serving director of the Department of Physics, University of Helsinki. A specialist in the physics of materials, he has been an active supporter of laboratory spectroscopy experiments and curriculum development for planetary science.Naming citation (MPC batch dated 2014-07-12), IAU / Minor Planet Center, via NASA/JPL
Where Keinonen is today
Seen from above the solar system on 2026-10-14: Keinonen is 2.74 au from the Sun and 2.56 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 10489 |
| Provisional designation | 1985 TJ1 |
| Orbit class | Main-belt Asteroid |
| Diameter | 11.2 km (#4,454 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.154 |
| Absolute magnitude (H) | 12.41 |
| Orbital period | 5.21 years |
| Semi-major axis | 3.00 au |
| Perihelion – aphelion | 2.74 – 3.27 au |
| Eccentricity | 0.0894 |
| Inclination | 10.9° |
| Closest distance between its orbit and Earth's (MOID) | 1.75 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also discovered on 15 October 1985
- (3564) Talthybius
- (3595) Gallagher
- (3639) Weidenschilling
- (4057) Demophon
- (4281) Pounds
- (4445) Jimstratton
- (4446) Carolyn
- (4665) Muinonen
- (4696) Arpigny
- (4739) Tomahrens
- (5463) Danwelcher
- (5554) Keesey