(21795) Masi Main-belt Asteroid
Discovered on 29 September 1999 by F. Mallia at Campo Catino.
Gianluca Masi (b. 1972), an amateur astronomer since 1980, is involved with several scientific projects, mainly on cataclysmic variable stars and minor planets. He has discovered a variable star and several minor planets. He collaborates with several institutions through several observing programs.Naming citation (20010509/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Masi is today
Seen from above the solar system on 2026-10-14: Masi is 2.51 au from the Sun and 3.44 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21795 |
| Provisional designation | 1999 SN9 |
| Orbit class | Main-belt Asteroid |
| Diameter | 3.15 km (#14,832 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.235 |
| Rotation period | 13.9 hours |
| Absolute magnitude (H) | 15.05 |
| Orbital period | 3.68 years |
| Semi-major axis | 2.38 au |
| Perihelion – aphelion | 1.93 – 2.84 au |
| Eccentricity | 0.192 |
| Inclination | 1.84° |
| Closest distance between its orbit and Earth's (MOID) | 0.938 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also discovered on 29 September 1999
- (19701) Aomori
- (20617) Richardgreenwood
- (20618) Daniebutler
- (21789) Frankwasser
- (21791) Mattweegman
- (22889) Donnablaney
- (22890) Ruthaellis
- (33789) Sharmacam
- (121328) Devlynrfennell
- (121330) Colbygoodloe
- (121332) Jasonhair
- (129879) Tishasaltzman