90 Antiope ( ) is a
double asteroid in the outer
asteroid belt. It was discovered on October 1, 1866, by
Robert Luther. In 2000, it was found to consist of two almost-equally-sized bodies orbiting each other. At average diameters of about 88 km and 84 km, both components are among the 500 largest
asteroids. Antiope is a member of the
Themis family of asteroids that share similar
orbital elements.