Active Asteroids

A near-Earth asteroid that brightens and sheds dust as it passes very close to the Sun — a 'rock comet' — and the parent body of the Geminid meteor shower, unusual for a shower whose source is an asteroid rather than a comet.

The prototype main-belt comet — an object on an ordinary asteroid-belt orbit that repeatedly develops a comet-like tail, carrying both an asteroid number and a comet designation.