NGC 7217

NGC 7217 is a field galaxy located approximately 50 million light-years away in the constellation Pegasus. It is a relatively isolated galaxy, not part of a larger cluster or group.

NGC 7217 is characterized by its multiple, prominent rings of stars and gas. These rings are believed to have formed through a complex interplay of gravitational interactions and the accretion of smaller galaxies. The outermost ring is particularly extended and features a population of younger, bluer stars, suggesting recent star formation activity. The inner rings are composed of older, redder stars.

One of the most intriguing features of NGC 7217 is the presence of a significant population of stars that orbit the galaxy in the opposite direction to the majority of its stars. This counter-rotating stellar population further supports the theory of past mergers with smaller galaxies, which may have disrupted the original disk of NGC 7217.

The central bulge of NGC 7217 is relatively small and contains a supermassive black hole, typical for spiral galaxies. The galaxy is classified as a peculiar spiral galaxy (type SA(r)b) due to its unusual ring structure. Its study provides insights into galaxy evolution, galaxy mergers, and the dynamics of galactic disks.