Astronomers today announced that an asteroid with six "comet-like" tails has been discovered. The asteroid, currently named P/2013 P5, was imaged twice in September by the Hubble Space Telescope. Its strange tails were seen changing position over the course of just a few days. A paper describing the asteroid was published today in the Astrophysical Journal Letters.
Astronomers currently hypothesize that these tails are made of dust that is expelled from the asteroid. The paper's authors believe that the asteroid has begun rotating so fast that parts of its surface are now breaking off from its surface.
"We were literally dumbfounded when we saw it," said David Jewitt, lead investigator on the paper and an astronomer at the University of California at Los Angeles. "Even more amazing, its tail structures change dramatically in just 13 days as it belches out dust. That also caught us by surprise. It's hard to believe we’re looking at an asteroid."
Modeling of the asteroid and its orbit have shown that its tails could have been formed by a series of "dust-ejection events" that happened between April and September of this year. Solar winds are believed to have strewn the dust into tail-like structures. That same radiation is also believed to have increased the asteroid's rate of rotation, causing surface dust to slide together and eventually off of the asteroid all together.
P/2013 P5's nucleus is only approximately 1,400 feet wide, making the asteroid's gravitational pull very weak. It is thought to be a piece of a larger asteroid that broke off around 200 million years ago.
"We were completely knocked out," said Jewitt. "This is just an amazing object to us, and almost certainly the first of many more to come."
(Image courtesy NASA, ESA, D.Jewitt/UCLA)