This ROSAT PSPC image shows more than 100 X-ray sources in the central region of the Hyades cluster, a nearby open star cluster about 45 parsecs (150 light-years) from the sun. The Hyades cluster is about 600 million years old; its member stars are quite young when compared to the 4.5 billion years age of the Sun. The entire cluster is distributed across more than 900 square degrees of the sky so this image only covers a small fraction of the Hyades. The ROSAT All-Sky Survey of the Hyades has identified over 185 of the 400 or more cluster stars as X-ray emitters at levels of 1 - 2 x 1028 erg/sec.
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