🐬 SH2-308 | Dolphin Head Nebula

This impressive cosmic structure is located in the constellation Canis Major, approximately 8° south of Sirius, the brightest star in the night sky. Officially named Sh2-308 (Sharpless 308), it is a giant H II region composed of ionized hydrogen.

The nebula's characteristic "bubble" shape is created by a Wolf-Rayet star at its center called EZ Canis Majoris. Such stars emit extremely powerful stellar winds during their pre-supernova phase. These winds push the surrounding gas, creating a giant cosmic bubble approximately 60 light-years in diameter. Therefore, SH2-308 is often referred to as the "Cosmic Bubble" in the literature.