by Ann » Fri Mar 10, 2023 6:20 am
bystander wrote: ↑Mon Mar 06, 2023 3:10 pm
Plunge into a Stellar Ocean
ESO Picture of the Week | 2023 Mar 06
potw2310a[1].jpgCredit: ESO/VPHAS+ team. Acknowledgement: Cambridge Astronomical Survey Unit
In this Picture of the Week, we take a deep plunge into the ocean of stars in the
IC4701 nebula. This
nebula is located in the
Sagittarius constellation, and it is twice as wide as the full Moon in the sky. The energetic light from newly-born stars
ionizes the hydrogen gas in the nebula, causing it to emit the intense reddish hue seen in this picture. The dark clouds in this image contain large amounts of
interstellar dust, too dense for the light of the background stars to pierce through it.
The IC4701 nebula is part of a
rich and vast complex of dust and gas within which new stars spring to life. When stars are born, most of them are cooler, redder, and less massive than our own Sun. Hotter, more massive stars are much rarer, and they quickly burn through all their fuel and die. This makes these brilliant blue and massive stars, and their surrounding glowing gas, beacons of recent star formation.
I finally identified it:
HD 167633 is a very hot star of spectral class O6.5V, and it definitely pumps a lot of ultraviolet light into many light-years of its vicinity, and it certainly helps ionize the gas there.
HD 167746 is an F-type giant illuminating yellow reflection nebula vdB 120. Both F-type HD star 167746 and O-type main sequence star HD 167633 are at reasonably the same distance, at about 6,000 light-years.
HD 167335 is a B-type foreground star, at a distance of "only" some 1,500 light-years.
Ann
[quote=bystander post_id=329618 time=1678115441 user_id=112005]
[url=https://www.eso.org/public/images/potw2310a/][size=125][b][i]Plunge into a Stellar Ocean[/i][/b][/size][/url]
ESO Picture of the Week | 2023 Mar 06
[quote]
[float=left][c]potw2310a[1].jpg[size=85][b][i]Credit: ESO/VPHAS+ team. Acknowledgement: Cambridge Astronomical Survey Unit[/i][/b][/size][hr][/hr][/c][/float]In this Picture of the Week, we take a deep plunge into the ocean of stars in the [url=https://simbad.u-strasbg.fr/simbad/sim-id?Ident=IC4701]IC4701[/url] nebula. This [url=https://en.wikipedia.org/wiki/Nebula]nebula[/url] is located in the [url=https://en.wikipedia.org/wiki/Sagittarius_(constellation)]Sagittarius[/url] constellation, and it is twice as wide as the full Moon in the sky. The energetic light from newly-born stars [url=https://en.wikipedia.org/wiki/Ionization]ionizes[/url] the hydrogen gas in the nebula, causing it to emit the intense reddish hue seen in this picture. The dark clouds in this image contain large amounts of [url=https://en.wikipedia.org/wiki/Interstellar_dust]interstellar dust[/url], too dense for the light of the background stars to pierce through it.
The IC4701 nebula is part of a [url=https://www.eso.org/public/news/eso1719/?lang]rich and vast complex of dust and gas[/url] within which new stars spring to life. When stars are born, most of them are cooler, redder, and less massive than our own Sun. Hotter, more massive stars are much rarer, and they quickly burn through all their fuel and die. This makes these brilliant blue and massive stars, and their surrounding glowing gas, beacons of recent star formation. [/quote]
[/quote]
I finally identified it:
[attachment=0]IC 4701 ESO annotated.png[/attachment]
HD 167633 is a very hot star of spectral class O6.5V, and it definitely pumps a lot of ultraviolet light into many light-years of its vicinity, and it certainly helps ionize the gas there.
HD 167746 is an F-type giant illuminating yellow reflection nebula vdB 120. Both F-type HD star 167746 and O-type main sequence star HD 167633 are at reasonably the same distance, at about 6,000 light-years.
HD 167335 is a B-type foreground star, at a distance of "only" some 1,500 light-years.
Ann