Astronomers have recently found a new active asteroid with comet-like tail in the Solar System's main asteroid belt between Mars and Jupiter.
The asteroid, called 62412 would be the first comet-like object seen in the Hygiea family of asteroids. The researchers discovered an unexpected tail on the asteroid, an object which had been known as a typical asteroid for over a decade.
Active asteroids are a newly recognized phenomenon. 62412 is only the 13th known active asteroid in the main asteroid belt. Carnegie's Scott Sheppard and Chadwick Trujillo of the Gemini Observatory estimated that there are likely about 100 of them in the main asteroid belt, based on their discovery.
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.
In the past, asteroids were thought to be mostly unchanging objects, but an improved ability to observe them has allowed scientists to discover tails and comas, which are the thin envelope of an atmosphere that surrounds a comet's nucleus.
Researchers found that 62412 have a very fast rotation that likely shifts material around its surface, some of which might be emitted to form the comet-like appearance. The tail might be created directly from ejected material off the fast rotating nucleus, or from ice within the asteroid subliming into water vapor after being freshly exposed on the surface.
They also find a density for 62412 typical of primitive asteroids and not consistent with the much lower- density comets. Further monitoring of this unusual object would help confirm the activity's source.
