Explanation:
Some 7,000 light-years away, this pair of open or galactic
star clusters is an easy
binocular target,
a lovely starfield in the
northern constellation
Perseus.
Also visible to
the unaided eye from dark sky areas,
it was cataloged in 130 BC by Greek astronomer
Hipparchus.
Now known as
h and
chi Persei, or
NGC 869(above right) and NGC 884, the clusters
themselves are separated by only a few hundred light-years and
contain stars much younger and hotter than the Sun.
In addition to being physically close together, the clusters' ages
based on
their individual stars are similar - evidence that
both clusters were likely a product of the same
star-forming region.
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