Topic summary
Asteroid moon
Extracted from the Wikipedia article Minor-planet moon.
Discovery milestones
In 1993, the first asteroid moon was confirmed when the Galileo probe discovered the small Dactyl orbiting 243 Ida in the asteroid belt. The second was discovered around 45 Eugenia in 1998. In 2001, 617 Patroclus and its same-sized companion Menoetius became the first known binary asteroids in the Jupiter trojans. The first trans-Neptunian binary after Pluto–Charon, 1998 WW31, was optically resolved in 2002.