(5639) Cuk Inner Main-belt Asteroid
Discovered on 9 August 1989 by Alu, J., Helin, E. F. at Palomar.
Matija Ćuk (b. 1978) is a dynamical astronomer and a discoverer of the BYORP mechanism, by which thermal radiation forces affect the orbits and rotational states of binary asteroids. For this and other contributions to the study of asteroids, Kuiper Belt objects, and the Moon, he received the 2014 Urey Prize.Naming citation (MPC batch dated 2015-01-05), IAU / Minor Planet Center, via NASA/JPL
Where Cuk is today
Seen from above the solar system on 2026-10-14: Cuk is 1.81 au from the Sun and 2.56 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 5639 |
| Provisional designation | 1989 PE |
| Orbit class | Inner Main-belt Asteroid |
| Diameter | 3.43 km (#14,156 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.198 |
| Rotation period | 23.3 hours |
| Absolute magnitude (H) | 14.96 |
| Orbital period | 2.52 years |
| Semi-major axis | 1.85 au |
| Perihelion – aphelion | 1.81 – 1.89 au |
| Eccentricity | 0.0229 |
| Inclination | 26.6° |
| Closest distance between its orbit and Earth's (MOID) | 0.837 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also discovered on 9 August 1989
← (5638) Deikoon · (5640) Yoshino →