(11781) Alexroberts Main-belt Asteroid
Discovered on 7 August 1966 by Boyden Observatory at Bloemfontein.
Scots-born Alexander William Roberts (1857-1938) emigrated in 1883 to South Africa, where he taught at and became principal of Lovedale Training School in Eastern Cape Province. He was one of the most prolific observers of variable stars in the southern hemisphere, and his records are maintained at the Boyden Observatory.Naming citation (20060809/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Alexroberts is today
Seen from above the solar system on 2026-10-14: Alexroberts is 2.54 au from the Sun and 3.34 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 11781 |
| Provisional designation | 1966 PL |
| Orbit class | Main-belt Asteroid |
| Diameter | 3.78 km (#13,256 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.409 |
| Rotation period | 4.19 hours |
| Absolute magnitude (H) | 14.11 |
| Orbital period | 3.63 years |
| Semi-major axis | 2.36 au |
| Perihelion – aphelion | 2.07 – 2.65 au |
| Eccentricity | 0.122 |
| Inclination | 7.31° |
| Closest distance between its orbit and Earth's (MOID) | 1.06 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Alexander
- (1688) Wilkens
- (4837) Bickerton
- (6941) Dalgarno
- (7660) Alexanderwilson
- (8479) Held
- (8486) Asherschel
- (8795) Dudorov
- (15434) Mittal
- (15608) Owens
- (17073) Alexblank
- (21397) Leontovich
- (21461) Alexchernyak
All asteroids named after someone called Alexander