Comets such as the Halley or the Hale-Bopp are small objects travelling through the solar system in long elliptical orbits.
Their characteristic tail appears every time they get close to the Sun.
The asteroids circling the Sun on the Main Belt between Mars and Jupiter are not supposed to have tails. But astronomers have recently discovered at least seven examples of asteroids that do. They are called main-belt comets and they are thought to be the remnants of a larger body smashed to pieces by a recent impact.
Serbian astronomer Bojan Novakovic and his team from the University of Belgrade worked on this theory. They focused on one of the seven main-belt comets, the P/2006 VW139, and their goal was to see if it could be assigned to a known family of asteroids.
Novakovic searched through the 398,841 asteroids on the AstDys database and narrowed down the possibilities to 24 candidates.
The next step was to look at the detailed orbital characteristics of these asteroids. This was possible thanks to the use of high-throughput compute – with a normal computer the job would take months. Novakovic used the computing services of Academic and Educational Grid Initiative of Serbia and was able to reduce the P/2006 VW139 family to just 11 members.
Novakovic concluded that P/2006 VW139 and its 11 partners are indeed part of a family. The siblings were formed about 7.5 million years ago, when a larger asteroid crashed with another object and disintegrated into smaller pieces.
The conclusion supports the theory that main-belt comets are born in collision events and not through some other means.
The telling tail of the P/2006 VW139 main-belt comet was discovered by the Pan-STARRS1 telescope. This picture is a long-exposure image taken by the New Technology Telescope at La Silla Observatory in Chile. (Credit: Sam Duddy and Stephen Lowry, University of Kent)
B. Novakovic et al. (2012). P/2006 VW139: A Main-Belt Comet Born in an Asteroid Collision? MNRAS 424, 1432-1441 (abstract)