(18876) Sooner Main-belt Asteroid
Discovered on 2 December 1999 by J. M. Roe at Oaxaca.
A sooner is a person settling on land in the early American west before the land was officially open to settlement. The name particularly honors the U.S. state of Oklahoma and the University of Oklahoma, alma mater of the discoverer.Naming citation (20020328/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Sooner is today
Seen from above the solar system on 2026-10-14: Sooner is 2.28 au from the Sun and 3.13 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 18876 |
| Provisional designation | 1999 XM |
| Orbit class | Main-belt Asteroid |
| Diameter | 3.07 km (#15,051 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.322 |
| Absolute magnitude (H) | 14.66 |
| Orbital period | 3.75 years |
| Semi-major axis | 2.41 au |
| Perihelion – aphelion | 1.83 – 3.00 au |
| Eccentricity | 0.241 |
| Inclination | 8.83° |
| Closest distance between its orbit and Earth's (MOID) | 0.846 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.