(11780) Thunder Bay Main-belt Asteroid
Discovered on 3 October 1942 by L. Oterma at Turku.
Thunder Bay, located on the shores of Lake Superior, is the most populous municipality in Northwestern Ontario, Canada. Formed in 1970 as the amalgamation of two cities, Thunder Bay is known as “the Lakehead” because it is Canada's westernmost port on the Great Lakes and the end of Great Lakes Navigation.Naming citation (MPC batch dated 2017-01-12), IAU / Minor Planet Center, via NASA/JPL
Where Thunder Bay is today
Seen from above the solar system on 2026-10-14: Thunder Bay is 2.96 au from the Sun and 3.83 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 11780 |
| Provisional designation | 1942 TB |
| Orbit class | Main-belt Asteroid |
| Diameter | 5.59 km (#9,583 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.287 |
| Rotation period | 295 hours |
| Absolute magnitude (H) | 13.19 |
| Orbital period | 4.06 years |
| Semi-major axis | 2.55 au |
| Perihelion – aphelion | 1.85 – 3.24 au |
| Eccentricity | 0.272 |
| Inclination | 9.36° |
| Closest distance between its orbit and Earth's (MOID) | 0.863 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.