An asteroid pair, or (if more than two bodies) an asteroid cluster, are asteroids which at some point in the past had very small relative velocities, and are typically formed either by a collisional break-up of a parent body, or from binary asteroids which became gravitationally unbound and are now following similar but different orbits around the Sun.[1]
The youngest asteroid pairs discovered as of 2022[update] include the main-belt asteroids P/2016 J1-A/B (separated c. 2010) and (458271) 2010 UM26/2010 RN221 (separated c. 2003).[3][4] The former pair is particularly remarkable for exhibiting comet-like activity due to water ice sublimation and rotational break-up.[3]