90 Antiope
Antiope is an asteroid discovered in 1866 by Robert Luther, the 90th asteroid discovered. It is named after an Amazon princess, sister of Hippolyte and daughter of Ares, who was taken prisoner by Heracles and later married Theseus. Alternatively, there is another Antiope in Greek legend, a daughter of Nycteus, king of Thebes, and mother of two children by Zeus.
In 2000, it was discovered that Antiope is a double asteroid, consisting of two individual bodies about 80 kilometers across and separated by 170 kilometers, orbiting around a common center. A complete revolution takes 16.5 hours. Their composition is C-type, which means that they are dark in colouring with a carbonate composition.
The discovery was made with the Keck Telescope at Mauna Kea using adaptive optics, allowing the two components to be resolved.