Explanation:
The first identified compact galaxy group,
Stephan's Quintet is featured in
this
eye-catching image constructed with data drawn from
the extensive Hubble Legacy Archive.
About 300 million light-years away, only four galaxies of the group
are actually locked in a cosmic dance of repeated close encounters.
The odd man out is
easy to spot, though.
The four
interacting galaxies
(NGC 7319, 7318A, 7318B, and 7317)
have an overall yellowish cast
and tend to have distorted
loops and tails, grown under the
influence of disruptive gravitational tides.
But the larger bluish galaxy, NGC 7320,
is much closer than the others.
Just 40 million light-years distant, it isn't part of the
interacting group.
In fact, individual stars in the foreground galaxy can be seen in
the sharp Hubble view, hinting that it is much closer than
the others.
Stephan's Quintet lies within the boundaries of the high flying
constellation
Pegasus.
Brian Marsden (1937, 2010)
