Explanation: NGC 6888, also known as the Crescent Nebula, is a about 25 light-years across blown by winds from its central, bright, massive star. A triumvirate of astroimagers ( Joe, Glenn, Russell) created this sharp portrait of the cosmic bubble. Their telescopic collaboration collected over 30 hours of narrow band image data isolating light from hydrogen and oxygen atoms. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. Visible within the nebula, NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away.
And from other sources, I gather that the bright star midway between the horns of the crescent is WR 136.
Re: APOD: NGC 6888: The Crescent Nebula (2021 Jun 17)
Posted: Thu Jun 17, 2021 9:29 pm
by WWW
Is that a tiny black dust cloud at the center of the nebula, to the side of the WR star?
Perhaps the star burped up a bit of soot?
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Re: APOD: NGC 6888: The Crescent Nebula (2021 Jun 17)
Posted: Fri Jun 18, 2021 2:26 am
by neufer
Click to play embedded YouTube video.
Re: APOD: NGC 6888: The Crescent Nebula (2021 Jun 17)
Posted: Fri Jun 18, 2021 9:43 am
by XgeoX
johnnydeep wrote: ↑Thu Jun 17, 2021 7:31 pm
Where's the crescent? In this APOD it looks more like an oblong meatball. This is one of the few crescent-like images I've found:
And what is that black pentagon nearby? Is it a foreground ink-black Bok globule?
Re: APOD: NGC 6888: The Crescent Nebula (2021 Jun 17)
Posted: Sat Jun 19, 2021 5:09 am
by NorthShoreDon
RE: Discussion of the image. It would be of great value to amateurs such as myself of you would simply place an arrow pointing out the star under discussion. Otherwise, as in this case, it is impossible to discern which is responsible for the nebula.
Re: APOD: NGC 6888: The Crescent Nebula (2021 Jun 17)