The Evolving Universe

Smithsonian Institution

Westerlund 2 star cluster

Westerlund 2 image

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.

  • Distance from Earth: 20,000-26,000 light years
  • Size: 15 light years
  • Telescope: Chandra X-ray Observatory
  • Light: X-ray (RGB 0.3-1.0, 1.0-2.0, 2.0-10.0 keV)