(7917) Hammergren Main-belt Asteroid
Discovered on 2 March 1981 by S. J. Bus at Siding Spring.
Mark Hammergren (b. 1964) is an astronomer at the Adler Planetarium in Chicago. His research investigates the shapes, compositions and internal structures of minor planets. He directs a summer outreach program for high-school students interested in astronomy.Naming citation (20120506/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Hammergren is today
Seen from above the solar system on 2026-10-14: Hammergren is 2.45 au from the Sun and 3.35 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 7917 |
| Provisional designation | 1981 EG5 |
| Orbit class | Main-belt Asteroid |
| Diameter | 3.18 km (#14,745 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.399 |
| Absolute magnitude (H) | 14.51 |
| Orbital period | 3.75 years |
| Semi-major axis | 2.41 au |
| Perihelion – aphelion | 2.10 – 2.72 au |
| Eccentricity | 0.130 |
| Inclination | 8.69° |
| Closest distance between its orbit and Earth's (MOID) | 1.09 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
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All asteroids named after someone called Mark
Also discovered on 2 March 1981
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