(458271) 2010 UM26 and (796785) 2010 RN221

Summary

(458271) 2010 UM26 and (796785) 2010 RN221 are a pair of main-belt asteroids that have identical orbits around the Sun. These two asteroids are thought to have dissociated from a binary system sometime in the 2000s, which would make them one of the youngest asteroid pairs known. The larger member of this pair, (458271) 2010 UM26 (or simply 2010 UM26), is about 760 m (2,490 ft) in diameter and was discovered on 10 November 2006 by the Spacewatch survey at Kitt Peak Observatory. The smaller member, (796785) 2010 RN221 (or simply 2010 RN221), is about 350 m (1,150 ft) in diameter and was discovered on 11 September 2010 by the Mount Lemmon Survey at Mount Lemmon Observatory. The similarity of the orbits of these asteroids was first noticed by astronomers in February 2022.