Blown by fast winds from a hot, massive star, this cosmic bubble is huge. SH2-308, also known as The Dolphin-head Nebula, is cataloged as Sharpless 2-308 and lies 5,000 light-years away toward the constellation Canis Major and covers a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured by narrowband filters in the deep image is dominated by the glow of ionized oxygen atoms mapped to a blue hue.
Image Credit & Copyright: Prabhu Kutti
