SH2-308 The Dolphin Nebula Wolf Rayet star

Swollen by the swift winds of a hot, massive star, this cosmic bubble is much larger than the dolphin it appears to be. Cataloged as Sharpless 2-308, it is located about 5,200 light-years away towards the constellation Canis Major and covers slightly more sky than a Full Moon. This corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright star near the center of the nebula. Wolf-Rayet stars have more than 20 times the mass of the Sun. The fast winds of this Wolf-Rayet star create the bubble-shaped nebula while sweeping away the slower-moving material that comes from an earlier phase of evolution. The wind-driven nebula is about 70,000 years old. The relatively faint emissions captured in the expansive foreground image are dominated by the glow of ionized oxygen atoms mapped to a blue hue.