(177771) Bretz Main-belt Asteroid
Discovered on 10 May 2005 by Mt. Lemmon Survey at Mount Lemmon.
Harley “J Harlen” Bretz (1882–1981) was an American geologist. His fieldwork of the Channeled Scablands on the Columbia River Plateau led him to propose that the landscape resulted from cataclysmic flooding. His theory has been vindicated by decades of evidence and the discovery of the ancient glacial Lake Missoula as the flood source.Naming citation (WGSBN Bull. 2, #7, 13), IAU / Minor Planet Center, via NASA/JPL
Where Bretz is today
Seen from above the solar system on 2026-10-14: Bretz is 2.07 au from the Sun and 2.60 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 177771 |
| Provisional designation | 2005 JA165 |
| Orbit class | Main-belt Asteroid |
| Diameter | 1.70 km (#17,274 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.267 |
| Absolute magnitude (H) | 16.13 |
| Orbital period | 4.22 years |
| Semi-major axis | 2.61 au |
| Perihelion – aphelion | 1.96 – 3.26 au |
| Eccentricity | 0.249 |
| Inclination | 2.59° |
| Closest distance between its orbit and Earth's (MOID) | 0.949 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.