NGC 7217 is an unbarred spiral galaxy in the constellation Pegasus.

NGC 7217 is a gas-poor system whose main features are the presence of several rings of stars concentric to its nucleus: three main ones –the outermost one being of the most prominent and the one that features most of the gas and star formation of this galaxy  plus several others inside the innermost one discovered with the help of the Hubble Space Telescope; a feature that suggests NGC 7217’s central regions have suffered several starbursts. There is also a very large and massive spheroid that extends beyond its disk.

Other noteworthy features this galaxy has are the presence of a number of stars rotating in the opposite direction around the galaxy’s center to most of them and two distinct stellar populations: one of intermediate age on its innermost regions and a younger, metal-poor version on its outermost ones.

It has been suggested these features were caused by a merger with another galaxy and, in fact, computer simulations show that NGC 7217 could have been a large lenticular galaxy that merged with one or two smaller gas-rich ones of late Hubble type becoming the spiral galaxy we see today.; however right now this galaxy is isolated in space, with no nearby major companions. More recent research, however, presents a somewhat different scenario in which NGC 7217’s massive bulge and halo would have been formed in a merger and the disk formed later (and is still growing) either accreting gas from the intergalactic medium or smaller gas-rich galaxies, or most likely from a previously existing reserve.