APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

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APOD Robot
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APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by APOD Robot » Tue Nov 12, 2024 5:05 am

Image NGC 6888: The Crescent Nebula

Explanation: How was the Crescent Nebula created? Looking like an emerging space cocoon, the Crescent Nebula, visible in the center of the featured image, was created by the brightest star in its center. A leading progenitor hypothesis has the Crescent Nebula beginning to form about 250,000 years ago. At that time, the massive central star had evolved to become a Wolf-Rayet star (WR 136), shedding its outer envelope in a strong stellar wind, ejecting the equivalent of our Sun's mass every 10,000 years. This wind impacted surrounding gas left over from a previous phase, compacting it into a series of complex shells, and lighting it up. The Crescent Nebula, also known as NGC 6888, lies about 4,700 light-years away in the constellation of Cygnus. Star WR 136 will probably undergo a supernova explosion sometime in the next million years.

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alex555

Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by alex555 » Tue Nov 12, 2024 9:30 am

I'm wondering what is the hole-like structure just to the left of WR 136.

Alex

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JohnD
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Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by JohnD » Tue Nov 12, 2024 10:45 am

Me too! It looks to cast a shadow of the main star on the structures nearer us. A dust cloud would surely have been long ago blown away?

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Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by johnnydeep » Tue Nov 12, 2024 1:28 pm

JohnD wrote: Tue Nov 12, 2024 10:45 am Me too! It looks to cast a shadow of the main star on the structures nearer us. A dust cloud would surely have been long ago blown away?
Looks like just an unusually opaque glob of dust to me. I google but didn't find anything that pointed it out.

crescent nebula and dark glob.jpg
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JohnD
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Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by JohnD » Tue Nov 12, 2024 2:41 pm

Way outside the Nebula, and happening to be in line of sight between us? 4700lys gives a lot of room for other things!
John

Gusty Winds

Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by Gusty Winds » Tue Nov 12, 2024 4:56 pm

Probably an "evaporating Gaseous Globule" on the line of sight between us and the nebula. See the October 22nd APOD.

Death fleer

Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by Death fleer » Wed Nov 13, 2024 4:52 am

Where is the Earth 250000years ago

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Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)

Post by Chris Peterson » Wed Nov 13, 2024 4:54 am

JohnD wrote: Tue Nov 12, 2024 2:41 pm Way outside the Nebula, and happening to be in line of sight between us? 4700lys gives a lot of room for other things!
John
Bok globules like that are associated with star forming regions. I think it's likely part of the nebula. You don't find them floating around in empty space.
Chris

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