When it was first spotted by astronomers at Space Watch on Kitt Peak, 2008 GO98 appeared to be one of many outer main belt asteroids moving through the night sky. 9 years later when my Catalina Sky Survey teammate Greg Leonard observed it with our 60 inch telescope on Mt. Lemmon it had a coma and a tail like a comet. Active asteroids like 2008 GO98 have asteroid orbits but sometimes show cometary activity which could be caused by a collision with another object and/or by thermal fracturing and ice sublimation caused by the slight warming they obtain from sunlight.
