Researchers publicly announced that the asteroid 1994 CC system, originally photographed by the NASA Goldstone Solar System Radar in June, is three separate rocks. The near-Earth asteroids that occasionally escape from an asteroid belt operating between Mars and Jupiter tend to be lone rocks, with 15 percent of near-Earth asteroids coming in pairs -- just one percent actually are three rocks. Source
Near-Earth asteroid found to be triplets New radar observations have revealed that a near-Earth asteroid is actually three rocks. Some 15 percent of these near-Earth asteroids are binaries. Even fewer, a mere one percent, are triples.
Radar imaging at NASA's Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth asteroid 1994 CC is a triple system. Asteroid 1994 CC encountered Earth within 2.52 million kilometres on June 10. Prior to the flyby, very little was known about this celestial body. 1994 CC is only the second triple system known in the near-Earth population. A team led by Marina Brozovic and Lance Benner, both scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, made the discovery.
1994 CC will be an exceptionally strong radar target at both Goldstone and Arecibo and we expect to be able to image it with the highest available resolutions (7.5 m for Arecibo and 19 m for Goldstone). This object will brighten below 13th magnitude in early June, but then it comes too close to the Sun for optical observations.
The 780 - 1700 metre wide asteroid 1994 CC will make a close pass (6.6 Lunar Distances, 0.0168 AU), travelling at 8.39 km/s, to the Earth-Moon system on the 10th June, 2009. At closest approach the asteroid will reach magnitude 13.