An Etymological Dictionary of Astronomy and Astrophysics
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An elliptical galaxy that is surrounded by thin shells of stars which are thought to have been ejected during a galaxy merger. Shell galaxies are different from ring galaxies in that the shells are much further away from the galaxy's centre and much fainter than the rings. Spectroscopy of the stars in the shell show that they are old whereas the stars in a ring galaxy are young.

→ shell; → galaxy.