WHEN a star is torn apart it's a rare event, happening only once every 10,000 years per galaxy. The odds of the light show also being captured by telescope or analysed by astronomers are slim.

So there was some excitement when an international group of astronomers reviewing observations taken in 2006 realised just what they were looking at.

A computer simulation shows what it would look like if you were near a black hole looking towards a galaxy like the Milky Way. Credit:Ute Kraus

The team, including Sydney University astrophysicist Sean Farrell, spent three years reviewing archival footage taken by the European Space Agency's X-ray telescope in the hope of spotting a rare event or object.

They found it in the form of a bright flare - a sign of a star being ripped apart by a supermassive black hole - in a galaxy some 500 million light years away.