Atira
163693 Atira (; provisional designation 2003 CP20) is a stony asteroid, dwelling in the interior of Earth's orbit. It is classified as a near-Earth object. Atira is a binary asteroid, a system of two asteroids orbiting their common barycenter. The primary component with a diameter of approximately 4.8 kilometers (3 miles) is orbited by a minor-planet moon that measures about 1 km (0.6 mi). Atira was discovered on 11 February 2003, by astronomers with the Lincoln Near-Earth Asteroid Research at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. To date, it is the only confirmed binary asteroid that orbits inside Earth's orbit.
軌道パラメータ
Orbit diagram
The Sun sits at the focus (orange). Earth's orbit is the grey circle at 1 AU. The red dot marks the object's position at the catalog epoch.