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Double Cluster

October 5, 2015

Two vigorous young star clusters circle high across the north on autumn evenings. Under dark skies, they’re just visible to the unaided eye as a hazy smudge of light. But binoculars or a small telescope begin to reveal their true nature — twin families of thousands of stars.

Together, they’re known as the Double Cluster. They’re about a third of the way up the northeastern sky at nightfall, below W-shaped Cassiopeia. They loop high across the north later on.

The two clusters lie at about the same distance — roughly 7500 light-years. And their stars are all about the same age — roughly 14 million years old. That means the two clusters probably formed together, from the same giant complex of gas and dust.

Together, the clusters contain perhaps 20,000 stars — one of the most impressive collections of stars in the entire galaxy.

That population includes many hot, massive stars that blaze thousands of times brighter than the Sun. Their brilliance is the reason the clusters are visible to the unaided eye despite their distance. Before long, though, the heaviest of these stars will begin to expire. And they’ll go out with a bang: Each will explode as a supernova, briefly shining many thousands of times brighter than all the other stars in the clusters combined.

After that generation of stars expires, the Double Cluster will lose much of its sparkle — leaving two clumps of middling stars traipsing through the galaxy together.


Script by Damond Benningfield, Copyright 2015

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