(21785) Mechain Main-belt Asteroid
Discovered on 21 September 1999 by M. Tichy at Klet.
Pierre François André Méchain (1744-1804) discovered many comets and deep-sky objects. A colleague and friend of Messier, he contributed much to Messier's catalogue of nebulae. Much of Méchain's career involved geodetic measurements along the Paris meridian, with the idea of defining the meter.Naming citation (20020624/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Mechain is today
Seen from above the solar system on 2026-10-14: Mechain is 2.69 au from the Sun and 2.83 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21785 |
| Provisional designation | 1999 SS2 |
| Orbit class | Main-belt Asteroid |
| Diameter | 4.49 km (#11,654 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.152 |
| Absolute magnitude (H) | 14.77 |
| Orbital period | 4.63 years |
| Semi-major axis | 2.78 au |
| Perihelion – aphelion | 2.30 – 3.25 au |
| Eccentricity | 0.172 |
| Inclination | 18.7° |
| Closest distance between its orbit and Earth's (MOID) | 1.30 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Pierre
- (2190) Coubertin
- (5439) Couturier
- (5442) Drossart
- (5523) Luminet
- (8190) Bouguer
- (10139) Ronsard
- (11401) Pierralba
- (11946) Bayle
- (12007) Fermat
- (12042) Laques
- (12324) Van Rompaey
- (12580) Antonini
All asteroids named after someone called Pierre