Binary asteroid

The term binary asteroid refers to a system in which two asteroids orbit their common center of mass, in analogy with binary stars. Binary asteroids where both bodies are roughly the same size are sometimes called "double asteroids" or "doublet asteroids". An example is the 90 Antiope system. Binary asteroids with a small satellite, called a "moonlet", have been more frequently observed (see 22 Kalliope, 45 Eugenia, 87 Sylvia, 107 Camilla, 121 Hermione, 130 Elektra, 283 Emma, 379 Huenna, etc.).
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