Arp 239

Arp 239, also known as UGC 05101, is a pair of interacting galaxies located approximately 180 million light-years away in the constellation Ursa Major. The system consists of two spiral galaxies, each distorted by the gravitational interaction with the other.

This interaction has created extended tidal tails composed of stars and gas, stretching far beyond the main bodies of the galaxies. These tails are a visual manifestation of the gravitational forces at play and demonstrate how interactions can reshape galaxies over cosmic timescales.

Arp 239 is included in the Atlas of Peculiar Galaxies, a catalog compiled by Halton Arp that showcases galaxies exhibiting unusual features. These features, such as tidal tails, bridges, and warped disks, are often the result of gravitational interactions or mergers. Arp's catalog aimed to highlight these peculiar galaxies and further the understanding of galaxy evolution.

Observations of Arp 239 across various wavelengths, including visible light, infrared, and radio waves, provide valuable data for studying the processes of star formation triggered by galactic interactions, as well as the distribution of gas and dust within the system. The intense gravitational forces involved can compress gas clouds, leading to bursts of star formation activity.