Space

Our Galaxy is Ancient, But New Stars Are Still Born (Picture)

Mark Hoffman
First Posted: Mar 28, 2013 11:55 PM EDT

Our galaxy is nearly as old as the Universe itself, but there is still some action in the form of newborn stars. The age of the Universe can be determined quite exactly to be 13.8 billion years, while our galaxy, the Milky Way, is also ancient — some of its stars are more than 13 billion years old. But even after such a long period, new objects still form while others are destroyed, for example the large gas cloud that this year is on the verge of being sucked into the super-massive black hole in the galaxy core. In this image, some of these newcomers can be seen, the young stars forming the cluster NGC 2547. And they are not too far away from Earth, at a distance of 1,500 light years, the cluster is in our neighbourhood of the galaxy.

"Young" is relative, as usual in galactic terms. Although their exact ages remain uncertain, astronomers estimate that NGC 2547’s stars range from 20 to 35 million years old. This compares to our Sun which is 4600 million years old and has not yet reached middle age. If the Sun would thus be a 40 year-old person, the bright stars in the picture are three-month-old babies.

Most stars do not form in isolation, but in rich clusters with sizes ranging from dozens to several thousands of stars. While NGC 2547 contains many hot stars that glow bright blue, a telltale sign of their youth, there are also some yellow or red stars which have already evolved to become red giants. Open star clusters like this usually only have comparatively short lives, of the order of several hundred million years, before they disintegrate as their component stars drift apart.

Clusters are key objects for astronomers studying how stars evolve through their lives. The members of a cluster are all born from the same material at about the same time, making it easier to determine the effects of other stellar properties.

The star cluster NGC 2547 lies in the southern constellation of Vela (The Sail), and is bright enough to be easily seen using binoculars.

Between the bright stars in this picture you can see plenty of other objects, especially when zooming in. Many are fainter or more distant stars in the Milky Way, but some, appearing as fuzzy extended objects, are galaxies, located millions of light-years beyond the stars in the field of view.

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