(21627) Sillis Main-belt Asteroid
Discovered on 13 July 1999 by LINEAR at Socorro.
Arnaud Georges Sillis (b. 1988) was awarded second place in the 2006 Intel International Science and Engineering Fair for his microbiology team project. He attends the Oregon Episcopal School, Portland, Oregon, U.S.A.Naming citation (20060711/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Sillis is today
Seen from above the solar system on 2026-10-14: Sillis is 2.37 au from the Sun and 3.11 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21627 |
| Provisional designation | 1999 NZ3 |
| Orbit class | Main-belt Asteroid |
| Diameter | 7.63 km (#6,970 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0550 |
| Rotation period | 46.8 hours |
| Absolute magnitude (H) | 14.47 |
| Orbital period | 4.08 years |
| Semi-major axis | 2.55 au |
| Perihelion – aphelion | 2.05 – 3.06 au |
| Eccentricity | 0.197 |
| Inclination | 12.4° |
| Closest distance between its orbit and Earth's (MOID) | 1.08 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Arnaud
All asteroids named after someone called Arnaud
Also discovered on 13 July 1999
- (11746) Thomjansen
- (11747) Libbykamen
- (12118) Mirotsin
- (12119) Memamis
- (12121) Greenwald
- (12572) Sadegh
- (15501) Pepawlowski
- (18821) Markhavel
- (18836) Raymundto
- (19582) Blow
- (19584) Sarahgerin
- (19585) Zachopkins