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Cepheus Nursery

May 14, 2010

Our home galaxy, the Milky Way, is fairly quiet. On average, it gives birth to about one new star a year. For a galaxy that already contains hundreds of billions of stars, that's not much.

One of the places where new stars are taking shape is in the constellation Cepheus -- a big stellar nursery known as Cepheus B.

The nursery is a cloud of gas and dust that spans several light-years. It contains hundreds of stars that are no more than a few million years old.

While the cloud itself might be considered the "mother" of all these newborn stars, the "father" of the brood appears to be a big star at the cloud's edge.

The star is many times more massive than the Sun, and tens of thousands of degrees hotter. Such a big, hot star produces enormous amounts of radiation. The radiation creates a "pressure wave" around the star.

As this wave hits the cloud of gas and dust, it squeezes it, forming dense blobs. These blobs then collapse under their own gravity to form new stars. Observations by two orbiting telescopes show that the stars that are closest to the big, hot star are the oldest, while those farthest away are the youngest -- providing strong evidence that a single star is helping give birth to hundreds more.

Look for Cepheus in the northeast this evening. Its brightest stars form a shape that resembles a child's drawing of a house. Cepheus B is just outside this pattern, but you need a telescope to see this family of young stars.

Script by Damond Benningfield, Copyright 2010

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