(11511) Billknopf Main-belt Asteroid
Discovered on 18 November 1990 by E. F. Helin at Palomar.
William Knopf (b. 1959) is an American Program Executive in the Planetary Science Division, NASA HQ, Washington, DC with expertise in physics, computer science and project management. He has participated in and overseen numerous projects, programs and spacecraft missions, including AMMOS, Cassini, EPOXI, Grail, Janus, Lunar Trailblazer, Psyche and VERITAS.Naming citation (WGSBN Bull. 4, #7, 7), IAU / Minor Planet Center, via NASA/JPL
Where Billknopf is today
Seen from above the solar system on 2026-10-14: Billknopf is 2.26 au from the Sun and 1.40 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 11511 |
| Provisional designation | 1990 WK2 |
| Orbit class | Main-belt Asteroid |
| Diameter | 6.09 km (#8,791 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.330 |
| Rotation period | 22.4 hours |
| Absolute magnitude (H) | 13.48 |
| Orbital period | 4.49 years |
| Semi-major axis | 2.72 au |
| Perihelion – aphelion | 2.22 – 3.22 au |
| Eccentricity | 0.184 |
| Inclination | 12.6° |
| Closest distance between its orbit and Earth's (MOID) | 1.25 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
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