(990) Yerkes Main-belt Asteroid
Discovered on 23 November 1922 by G. Van Biesbroeck at Williams Bay.
Where Yerkes is today
Seen from above the solar system on 2026-10-14: Yerkes is 2.14 au from the Sun and 1.66 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 990 |
| Provisional designation | A922 WE |
| Orbit class | Main-belt Asteroid |
| Diameter | 21.4 km (#2,033 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0610 |
| Rotation period | 24.6 hours |
| Absolute magnitude (H) | 11.94 |
| Orbital period | 4.36 years |
| Semi-major axis | 2.67 au |
| Perihelion – aphelion | 2.09 – 3.25 au |
| Eccentricity | 0.217 |
| Inclination | 8.78° |
| Closest distance between its orbit and Earth's (MOID) | 1.09 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.