Dimorphos is probably a piece of Didymos

Last September, NASA purposefully smashed a spacecraft into Dimorphos, a 160m-wide space rock orbiting a larger asteroid named Didymos. The goal of the mission, called DART (the Double Asteroid Redirection Test), was to demonstrate humanity's ability to redirect hazardous asteroids away from Earth. That part of the mission was a success above and beyond all expectations.