Astronomy Picture of the Day

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 October 21

SH2-308: The Dolphin-Head Nebula

Image Credit & Copyright: Nik Szymanek

Explanation: Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,000 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That 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 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. Presenting a mostly harmless outline, SH2-308 is also known as The Dolphin-head Nebula.

A Look at The Universe

Witch’s Broom in the Western Veil of the Veil Nebula

(Sorry I tried to make this picture bigger and it did not work. :o{ )

The New General Catalogue, an astronomical compendium of deep space objects, names this nebula NGC 6960. Its unofficial name is a touch more poetic: Witch’s Broom. Located in the Veil Nebula, it’s part of the remnants of a star 20 times the size of our sun that went supernova, exploding roughly 8,000 years ago. The long, slender filaments of the Witch’s Broom are part of an expanding blast wave from the supernova that’s shocking, heating, and transforming interstellar gasses as it goes. The bright spot at the nebula’s upper edge is the giant star 52 Cygni in the constellation Cygnus.

To see the above picture larger