Ouch! Subaru telescope catches astroid prang

Astronomers have announced evidence that a main-belt asteroid called 493 Griseldis took a hit from another object in March of this year.

Shots taken by the Subaru 8m optical telescope showed that Griseldis had grown a tail – and unlike a comet's tail, which points away from the sun, the asteroid's tail was “not in the antisolar direction”.

The other hint that the “extended feature” was debris from a collision is that it came and went fairly quickly. By 24 March, the University of Hawaii's 2.2m telescope couldn't find it, a finding confirmed in April by observations on the 6.5m Magellan.

Archival images from 2010 and 2012 also showed a tail-less Griseldis.

Griseldis, orbiting at between 2.594 AU and 3.653 AU, was discovered in 1902 by German astronomer Max Wolf, and apart from it getting an entry in the Directory of Minor Planet Names, this is pretty much the most exciting thing that it's done since it was first photographed. ®

In this four-panel image, 493 Griseldis is shown with the tail at bottom right of the last panel, a composite of the other three panels. University of Hawaii at ManoaClick to embiggen.