(21042) Sibeck Outer Main-belt Asteroid
Discovered on 16 August 1990 by E. W. Elst at La Silla.
David Gary Sibeck (b. 1958) is an American space physicist who revolutionized our understanding of how the solar wind interacts with the Earth's magnetosphere and ionosphere. He established how variable solar-wind forcing drives magnetospheric dynamics, and he provided the statistical framework underpinning many modern analyses of the day-side magnetopause.Naming citation (WGSBN Bull. 6, #13, 4), IAU / Minor Planet Center, via NASA/JPL
Where Sibeck is today
Seen from above the solar system on 2026-10-14: Sibeck is 2.85 au from the Sun and 1.99 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21042 |
| Provisional designation | 1990 QT7 |
| Orbit class | Outer Main-belt Asteroid |
| Diameter | 9.63 km (#5,324 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0830 |
| Absolute magnitude (H) | 13.51 |
| Orbital period | 5.83 years |
| Semi-major axis | 3.24 au |
| Perihelion – aphelion | 2.82 – 3.66 au |
| Eccentricity | 0.131 |
| Inclination | 0.747° |
| Closest distance between its orbit and Earth's (MOID) | 1.83 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called David
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- (5845) Davidbrewster
- (5920) Davidbell
- (5965) Meisel
- (6033) Southwood
- (6111) Davemckay
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All asteroids named after someone called David
Also discovered on 16 August 1990
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