Ring Galaxy Zw II 28: Galaxy With the Hole in the Middle

Galaxy Zw II 28 possesses a mysterious ring shape. 

Researchers believe ring galaxies form when one galaxy slices through the disc of another, larger, one, though without much destruction as might be expected, as galaxies mostly contain empty space. 

This disruption should redistribute the material in both galaxies to form a dense central core, encircled by bright stars, iintensely forming new stars in the outer ring. 

The pink and purple loop of Zw II 28 does not represent a typical ring galaxy due to its lack of a visible central companion. 

However, a companion may lurk just inside the ring. Image released March 11, 2013.

Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

Hoag's Object

Hoag's Object, a ring galaxy 600,000 light yrs away, with another ring galaxy visible through the gap.

Hoag's Object is a non-typical galaxy of the type known as a ring galaxy.

The appearance of this object has interested amateur astronomers as much as its uncommon structure has fascinated professionals.

The galaxy is named after Arthur Allen Hoag who discovered it in 1950 and identified it as either a planetary nebula or a peculiar galaxy with 8 billion stars.