(136617) 1994 CC
Introduction '''''' is a sub-kilometer trinary asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group.
Discovery  was discovered by Spacewatch's Jim Scotti at Kitt Peak National Observatory on 3 February 1994.In June 2009 it was shown to be a triple system, i.e. the largest body is orbited by two satellites; only about one percent (1%) of near-Earth asteroids observed by a radar are found to be triple systems such as this one. The only other unambiguously identified triple asteroids in the near-Earth population are , which was discovered to be a triple system in 2008, and 3122 Florence, which was found to be a triple system in 2017.
Observations Radar images of  at two different times with its two moonsA team of NASA's Jet Propulsion Laboratory (JPL) (Pasadena, California) scientists led by Marina Brozovic and Lance Benner, made the discovery using radar imaging at NASA's Goldstone Solar System Radar on June 12 and June 14, 2009.They showed that the near-Earth asteroid  is a triple system, which encountered Earth within 2.52 million kilometers on June 10, 2009.This relatively close approach to Earth made the discovery possible, as before the approach, scientists knew very little about this asteroid. In fact,  is only the second triple system known in the near-Earth objects population.1994 CC consists of a central object about 700 meters in diameter that has two moons revolving around it. Scientists' preliminary analysis of the system suggests that the moons are at least 50 meters in diameter. In a similar study, the radar observations at Arecibo Observatory in Puerto Rico, led by the Mike Nolan, also confirmed the detection of all three objects. The scientists plan to use the combined observations from the Goldstone and Arecibo observatories to study 's orbital and physical properties further.The next similar Earth flyby for the asteroid  will happen in 2074 when the triple system is projected to fly past Earth at a distance of 2.5 million kilometers.
Orbital characteristics of satellites The orbital properties of the satellites are listed in this table. The orbital planes of both satellites are inclined relative to each other, by approximately 16°. Such a large inclination is suggestive of past evolutionary events (e.g. close encounter with a terrestrial planet, mean-motion resonance crossing) that may have excited their orbits from a coplanar configuration to an inclined state. Name  Mass109 kg  Semi-major axiskm  Orbital perioddays  Eccentricity  Inclination(relative to asteroid)° Beta  ~6  1.7  1.243  0.002  95 Gamma  ~1  6.1  8.376  0.192  79
Numbering and naming This minor planet was numbered by the Minor Planet Center on 5 December 2006., it has not been named.
See also * List of exceptional asteroids* 2004 FH* 87 Sylvia* 433 Eros*
References
External links *  Spacewatch Discoveries for 1994, Spacewatch NEO Detections by Year, University of Arizona*  Official press release by NASA on triplet system*  (136617) 1994 CC compiled by Wm. Robert Johnston* Julia Fang, "Orbits of Near-Earth Asteroid Triples 2001 SN263 and 1994 CC: Properties, Origin, and Evolution", * * *