Arp 230 is a galaxy of an uncommon or peculiar shape which is how it earned its place in the Atlas of Peculiar Galaxies produced by Halton Arp. Its irregular shape is probably the result of a violent collision with another galaxy sometime in the past.
The collision likely caused the formation of the galaxy’s polar ring. The outer ring surrounding the galaxy consists of gas and stars. It rotates over the poles of the galaxy. If the orbit of the smaller of the two galaxies that created Arp 230 was perpendicular to the disk of the larger galaxy when they collided, the smaller galaxy would have been ripped apart and formed the polar ring.
Image Credit: ESA / NASA