Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 June 26
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Young Star Cluster Westerlund 2
Credit: X-ray; Y.Nazé, G.Rauw, J.Manfroid (Université de Liège), CXC, NASA
Infrared; E.Churchwell (University of Wisconsin), JPL, Caltech, NASA

Explanation: Dusty stellar nursery RCW 49 surrounds young star cluster Westerlund 2 in this remarkable composite skyscape from beyond the visible spectrum of light. Infrared data from the Spitzer Space Telescope is shown in black and white, complementing the Chandra X-ray image data (in false colour) of the hot energetic stars within the cluster's central region. Looking toward the grand southern constellation Centaurus, both views reveal stars and structures hidden from optical telescopes by obscuring dust. Westerlund 2 itself is a mere 2 million years old or less, and contains some of our galaxy's most luminous, massive and therefore short-lived stars. The infrared signatures of proto-planetary disks have also been identified in the intense star forming region. At the cluster's estimated distance of 20,000 light-years, the square marking the Chandra field of view would be about 50 light-years on a side.

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