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.

September 28, 1997
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A Wolf Rayet Star Bubble
Credit: Anglo-Australian Telescope photograph by David Malin
Copyright: Anglo-Australian Telescope Board

Explanation: What's a Wolf-Rayet star, and how did it create that spherical bubble and sweeping arc? A Wolf-Rayet star is a star that originated with a mass over 40 times that of our Sun. An extremely hot, luminous star, it has since expelled shells of material through its strong stellar wind which could account for the bubble shaped nebula that surrounds it. But astronomers are unsure how the central Wolf-Rayet created both the bubble and the arc seen above, and even whether it acted alone in doing so. Together, this bubble and the arc are known as NGC 2359.

Tomorrow's picture: Jupiter And Family

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.