SH2-308 - Dolphin-Head Nebula

Sh2-308, also designated as Sharpless 308, RCW 11, or LBN 1052, and commonly known as the Dolphin-Head Nebula, is an H II region located near the center of the constellation Canis Major, composed of ionised hydrogen. It is about 8 degrees south of Sirius, the brightest star in the night sky. The nebula is bubble-like and surrounds a Wolf–Rayet star named EZ Canis Majoris. This star is in the brief, pre-supernova phase of its stellar evolution. The nebula is about 4,530 light-years (1,389 parsecs) away from Earth, but some sources indicate that both the star and the nebula are up to 5,870 ly (1,800 pc) away.

(Source: Wikipedia)