# Astronomy Picture of the Day

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.

2018 April 19

NGC 7635: The Bubble Nebula
Image Credit: NASA, ESA, Hubble Heritage Team - Reprocessing by Maksim Kakitsev

Explanation: Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 7 light-year diameter bubble offers evidence of violent processes at work. Above and left of the Bubble's center is a hot, O-type star, several hundred thousand times more luminous and some 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula and associated cloud complex lie a mere 7,100 light-years away toward the boastful constellation Cassiopeia. This sharp, tantalizing view of the cosmic bubble is a composite of Hubble Space Telescope image data from 2016, reprocessed to present the nebula's intense narrowband emission in an approximate true color scheme.

Tomorrow's picture: pixels in space

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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