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APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Tue Nov 12, 2024 5:05 am
by APOD Robot
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.
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Tue Nov 12, 2024 9:30 am
by alex555
I'm wondering what is the hole-like structure just to the left of WR 136.
Alex
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Tue Nov 12, 2024 10:45 am
by JohnD
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?
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Tue Nov 12, 2024 1:28 pm
by johnnydeep
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.
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Tue Nov 12, 2024 2:41 pm
by JohnD
Way outside the Nebula, and happening to be in line of sight between us? 4700lys gives a lot of room for other things!
John
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Tue Nov 12, 2024 4:56 pm
by Gusty Winds
Probably an "evaporating Gaseous Globule" on the line of sight between us and the nebula. See the October 22nd APOD.
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Wed Nov 13, 2024 4:52 am
by Death fleer
Where is the Earth 250000years ago
Re: APOD: NGC 6888: The Crescent Nebula (2024 Nov 12)
Posted: Wed Nov 13, 2024 4:54 am
by Chris Peterson
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.
