(242321) Billtilden Outer Main-belt Asteroid
Discovered on 20 November 2003 by CSS at Catalina.
James Wilson Tilden (1904–1988) was an American entomologist, best known for his books Butterflies of the San Francisco Bay and A Field Guide to Western Butterflies. He made lasting contributions to the study of butterfly species in western North America.Naming citation (WGSBN Bull. 6, #7, 9), IAU / Minor Planet Center, via NASA/JPL
Where Billtilden is today
Seen from above the solar system on 2026-10-14: Billtilden is 2.98 au from the Sun and 2.25 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 242321 |
| Provisional designation | 2003 WB170 |
| Orbit class | Outer Main-belt Asteroid |
| Diameter | 6.33 km (#8,476 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0770 |
| Absolute magnitude (H) | 14.79 |
| Orbital period | 7.97 years |
| Semi-major axis | 3.99 au |
| Perihelion – aphelion | 2.90 – 5.08 au |
| Eccentricity | 0.273 |
| Inclination | 11.5° |
| Closest distance between its orbit and Earth's (MOID) | 1.92 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
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