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August 9, 2012

Most stars are born with other stars, and tonight the southern sky features a dramatic example — a rich young cluster filled with thousands of stars that formed together.

The cluster is named M11, but because its brightest stars look like a flock of wild ducks, it’s also called the Wild Duck cluster. Through binoculars, it looks like a patch of mist; a backyard telescope reveals hundreds of stars.

M11 is about 230 million years old. It’s 6700 light-years away, toward the center of the Milky Way galaxy.

As a result of that location, its stars have a higher abundance of heavy elements than the Sun does. Such elements are created in the hearts of stars and expelled into space as the stars die. M11 is closer to the center of the Milky Way, where there are more stars than out in our region of the galaxy — hence there are more abundant supplies of heavy elements.

Compared to the Sun, the stars of M11 have about 25 percent more iron relative to hydrogen, which makes up the bulk of all stars. Since iron is a key ingredient for rocky planets like Earth, some of the cluster’s stars could have planets similar to our own. Any inhabitants would be treated to a sky full of brilliant stars.

You can see M11 in the southern sky this evening. The cluster is in the small constellation Scutum, the shield, which is just north of teapot-shaped Sagittarius. The beautiful cluster shows us an environment like the one where the Sun and Earth resided when they were young.

Script by Ken Croswell, Copyright 2012


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