(20617) Richardgreenwood Outer Main-belt Asteroid
Discovered on 29 September 1999 by LINEAR at Socorro.
Richard Greenwood (b. 1957) is an English senior research fellow at The Open University who specializes in using oxygen isotopic analyses of extraterrestrial material to understand the origin and early evolution of the Solar System. He has also written a book on meteorites that was geared towards a general audience.Naming citation (WGSBN Bull. 6, #11, 30), IAU / Minor Planet Center, via NASA/JPL
Where Richardgreenwood is today
Seen from above the solar system on 2026-10-14: Richardgreenwood is 3.40 au from the Sun and 4.31 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 20617 |
| Provisional designation | 1999 SA7 |
| Orbit class | Outer Main-belt Asteroid |
| Diameter | 17.5 km (#2,580 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0690 |
| Absolute magnitude (H) | 12.44 |
| Orbital period | 5.81 years |
| Semi-major axis | 3.23 au |
| Perihelion – aphelion | 3.04 – 3.42 au |
| Eccentricity | 0.0587 |
| Inclination | 21.4° |
| Closest distance between its orbit and Earth's (MOID) | 2.13 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Richard
- (4143) Huziak
- (4252) Godwin
- (5391) Emmons
- (5567) Durisen
- (6368) Richardmenendez
- (6893) Sanderson
- (7392) Kowalski
- (7845) Mckim
- (7966) Richardbaum
- (8331) Dawkins
- (8717) Richviktorov
- (9725) Wainscoat
All asteroids named after someone called Richard
Also discovered on 29 September 1999
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- (20618) Daniebutler
- (21789) Frankwasser
- (21791) Mattweegman
- (21795) Masi
- (22889) Donnablaney
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- (33789) Sharmacam
- (121328) Devlynrfennell
- (121330) Colbygoodloe
- (121332) Jasonhair
- (129879) Tishasaltzman