Dumbbell Nebula

StarDate: September 6, 2009

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Foxes are shy and elusive little creatures, so it's not surprising that the celestial fox is hard to see.

Like a fox, Vulpecula is long and skinny. It's about halfway between two of the stars of the Summer Triangle: Deneb, which is high in the east at nightfall, and Altair, which is in the southeast.

Don't bother looking for the outline of a fox, though -- you won't find one. In fact, unless you have dark skies, you won't see anything at all, because Vulpecula's stars are quite faint.

Through a telescope, one of the fox's few impressive sights is a blob of light known as the Dumbbell Nebula. It's a glowing cloud of gas expelled by a dying star. The cloud's outline resembles a dumbbell. It's one of the brightest nebulas of its class, even though it's more than 1200 light-years away.

The nebula formed when a star that was once much like the Sun reached the end of its life. The star had puffed up like a big balloon in response to changes in its core. As the core stopped producing nuclear reactions, the outer layers blew away into space. That probably happened at least 10,000 years ago.

As the layers of gas expand, they're zapped by radiation from the star's dead core, which is known as a white dwarf. This energy makes the gas light up like the inside of a fluorescent bulb.

The gas is continuing to expand into space. Over time, it'll grow so thin that it will vanish from view -- and the Dumbbell Nebula will disappear.

Script by Damond Benningfield, Copyright 2009

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