Westerlund 2 star cluster
Credit: NASA/CXC/Liege
Observers: Y. Naeze, G. Rauw and Gordon Garmire
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This open cluster of very young stars - only one to two million years old - contains some of the hottest, brightest and largest stars in our galaxy. Because the cluster is heavily obscured by dust, we can only study these stars with infrared and X-ray telescopes. Because all of the sars in the cluster are about the same age, astronomers can examine how differences in size and weight affect a star's life.