(20413) Josephdemartini Main-belt Asteroid
Discovered on 28 August 1998 by LINEAR at Socorro.
Joseph DeMartini (b. 1996) is an American scientist who completed his Ph.D. at the University of Maryland in 2025. His work focuses on simulating the behavior of asteroid surfaces and interiors, especially under tidal stresses such as the close encounter of Apophis with Earth in 2029. He won the Schweickart Prize for planetary defense in 2024.Naming citation (WGSBN Bull. 6, #11, 19), IAU / Minor Planet Center, via NASA/JPL
Where Josephdemartini is today
Seen from above the solar system on 2026-10-14: Josephdemartini is 1.82 au from the Sun and 0.905 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 20413 |
| Provisional designation | 1998 QY91 |
| Orbit class | Main-belt Asteroid |
| Diameter | 2.35 km (#16,522 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.386 |
| Rotation period | 2.22 hours |
| Absolute magnitude (H) | 15.3 |
| Orbital period | 3.52 years |
| Semi-major axis | 2.31 au |
| Perihelion – aphelion | 1.76 – 2.86 au |
| Eccentricity | 0.238 |
| Inclination | 3.47° |
| Closest distance between its orbit and Earth's (MOID) | 0.768 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
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