(20489) Lissauer Main-belt Asteroid
Discovered on 22 July 1999 by LINEAR at Socorro.
Jack J. Lissauer (b. 1957) is an American scientist at the Ames Research Center. His dynamical studies include how galactic tides influence the delivery of comets and how the asteroid belt influences planetary stability. As a textbook author, he has introduced a new generation of students to planetary science, including asteroids, comets, and meteors.Naming citation (WGSBN Bull. 6, #11, 23), IAU / Minor Planet Center, via NASA/JPL
Where Lissauer is today
Seen from above the solar system on 2026-10-14: Lissauer is 2.41 au from the Sun and 3.39 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 20489 |
| Provisional designation | 1999 OJ2 |
| Orbit class | Main-belt Asteroid |
| Diameter | 6.94 km (#7,727 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.304 |
| Absolute magnitude (H) | 12.96 |
| Orbital period | 4.17 years |
| Semi-major axis | 2.59 au |
| Perihelion – aphelion | 2.32 – 2.86 au |
| Eccentricity | 0.104 |
| Inclination | 12.4° |
| Closest distance between its orbit and Earth's (MOID) | 1.37 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Jack
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All asteroids named after someone called Jack