NGC 7331 and four background galaxies, NGC 7335, NGC 7336, NGC 7337 and NGC 7340, are collectively called the Deer Lick Group
. According to Wikipedia
, the four background galaxies are sometimes called "the fleas".
Very interesting, at least to me, is that the "fleas" of the Deer Lick Group are at about the same distance from us as Stephan's Qiuntet, or 300 million light-years!
But one of the galaxies that seems to belong to Stephan's Quintet, NGC 7320, is a foreground object. The Hubble picture at left clearly shows that one of the galaxies has a faint bulge, a tiny nucleus, and a knotty blue disk full of regions of star formation. Another Hubble image
brings out the difference between NGC 7320 and the "real" Stephan's Quintet galaxies even more strongly.
A faint fuzzy companion galaxy of NGC 7331?
According to Wikipedia, NGC 7320 is only 39 million light-years away, making it a possible (but perhaps not probable) physical member of an extended NGC 7331 group of galaxies. NGC 7331 itself is believed to be a distance of 50 million light-years.
But if NGC 7320 is not a member of a physical NGC 7331 group, today's APOD is showing us just the sort of galaxy that probably is. I have marked it with an arrow in the picture at right.
Note how faint this galaxy is. Note its color. It's not yellow, so it doesn't contain a rich massive collection of small red stars. It's not blue, so it displays little or no star formation. To me, this galaxy looks very much like a faint fuzzy lenticular or spheroidal
companion galaxy of NGC 7331.
Unfortunately, I can't find this galaxy with the help of my software Guide. Does anyone else know anything about this galaxy?
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