(9491) Thooft Main-belt Asteroid
Discovered on 25 March 1971 by van Houten, C. J., van Houten-Groeneveld, I., Gehrels, T. at Palomar.
Gerardus 't Hooft (b. 1946) is professor of physics at University of Utrecht. Together with his colleague M. J. G. Veltman he won the 1999 Nobel Prize in physics, awarded for placing the theory of particle physics on a firmer mathematical foundation and for elucidating the quantum structure of electroweak interactions.Naming citation (20000320/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Thooft is today
Seen from above the solar system on 2026-10-14: Thooft is 2.33 au from the Sun and 2.87 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 9491 |
| Provisional designation | 1205 T-1 |
| Orbit class | Main-belt Asteroid |
| Diameter | 2.24 km (#16,713 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.268 |
| Absolute magnitude (H) | 15.08 |
| Orbital period | 3.30 years |
| Semi-major axis | 2.21 au |
| Perihelion – aphelion | 1.92 – 2.51 au |
| Eccentricity | 0.134 |
| Inclination | 5.05° |
| Closest distance between its orbit and Earth's (MOID) | 0.913 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also discovered on 25 March 1971
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