(6857) Castelli Main-belt Asteroid
Discovered on 19 August 1990 by E. F. Helin at Palomar.
Benedetto Castelli (1578-1643) studied mathematics in Padova and was a favorite pupil of Galileo, with whom he discussed the significance of the phases of Venus in the Copernican theory. He also published works on fluids in motion, and is universally recognized as the founder of modern hydrodynamics.Naming citation (MPC batch dated 2017-03-12), IAU / Minor Planet Center, via NASA/JPL
Where Castelli is today
Seen from above the solar system on 2026-10-14: Castelli is 2.75 au from the Sun and 2.04 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 6857 |
| Provisional designation | 1990 QQ |
| Orbit class | Main-belt Asteroid |
| Diameter | 8.31 km (#6,295 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0730 |
| Absolute magnitude (H) | 14.25 |
| Orbital period | 3.52 years |
| Semi-major axis | 2.31 au |
| Perihelion – aphelion | 1.85 – 2.77 au |
| Eccentricity | 0.198 |
| Inclination | 9.20° |
| Closest distance between its orbit and Earth's (MOID) | 0.859 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.