A two-person team of Carnegie’s Scott Sheppard and Chadwick Trujillo of the Gemini Observatory has discovered a new active asteroid, called 62412, in the Solar System’s main asteroid belt between Mars and Jupiter. It is the first comet-like object seen in the Hygiea family of asteroids.
Active asteroids are a newly recognized phenomenon. 62412 is only the 13th known active asteroid in the main asteroid belt. Sheppard and Trujillo estimate that there are likely about 100 of them in the main asteroid belt, based on their discovery.
Active asteroids have stable orbits between Mars and Jupiter like other asteroids. However, unlike other asteroids, they sometimes have the appearance of comets, when dust or gas is ejected from their surfaces to create a sporadic tail effect. Sheppard and Trujillo discovered an unexpected tail on 62412, an object which had been known as a typical asteroid for over a decade. Their findings reclassify it as an active asteroid. The reasons for this loss of material and subsequent tail in active asteroids are unknown, although there are several theories such as recent impacts or sublimation from solid to gas of exposed ices.
Discoveries such as this one can help researchers determine the processes that cause some asteroids to become active. Further monitoring of this unusual object will help confirm the activity’s source.
Sheppard and Trujillo have a paper about this work in press at The Astronomical Journal.