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Messy Demise

March 22, 2010

Just because a star is dead doesn't mean it can't be interesting. Take the case of two dead stars in a nearby galaxy. One of the stars appears to be ripping the other to shreds, creating a spectacular fireworks display.

A team led by Jimmy Irwin of the University of Alabama discovered the system in observations made by the orbiting Chandra X-Ray Observatory. The system is in a cluster of stars that's 65 million light-years away.

The system is producing a bright flare of X-rays. The flare contains lots of oxygen, but no hydrogen -- the most abundant element in "normal" stars like the Sun.

From this and other factors, the team deduced that the system probably consists of two stellar corpses: a white dwarf and a black hole.

A white dwarf is the final stage of life for a star like the Sun. It's a small, dense ball of carbon and oxygen that no longer produces energy, but that shines because it's extremely hot. A black hole is packed so tightly that not even light can escape from it. This black hole may be a thousand times as massive as the Sun -- a member of a class known as "intermediate" black holes, which may form from the mergers of smaller black holes.

The white dwarf probably wandered too close to the black hole, and was ripped apart by its tremendous gravity. The remains have spread out around the black hole. Over time, some of this material will fall into the black hole, while the rest will cool and fade from sight.

Script by Damond Benningfield, Copyright 2010

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