ESO 306-17

ESO 306-17 is a fossil group giant elliptical galaxy in the Columba constellation, about 1.07 million light-years in diameter, and roughly 517 million light-years away.

The galaxy is situated alone in a volume of space about it. It is theorized that the galaxy cannibalized its nearest companions, hence, being a fossil group. The galaxy is a giant elliptical of type cD3 (E+3), one of the largest types of galaxies.