Don Quixote has been considered asteroidal since its discovery in 1983, despite its comet-like orbit. We found activity in this object during its 2009 and 2018 apparitions, leading us to believe that it really is an active comet. But are there other objects like Don Quixote? I monitored a sample of ~100 asteroids that are somewhat likely to turn active, too, over a period of more than 4 years. Bottom line: Don Quixote is rather unique.

Near-Earth asteroid Don Quixote has long since been considered a good candidate for an inactive comet nucleus due to its comet-like orbit. Since its discovery in 1983, comet-like has never been observed - until we observed this object with the Spitzer Space Telescope…