APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

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Expand view Topic review: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by HenryLiams » Mon Sep 02, 2024 10:59 am

The Cocoon Nebula (IC 5146) is a stunning star-forming region located about 4,000 light-years away. This vibrant nebula showcases young, hot stars and glowing hydrogen gas, highlighting the active process of star formation.

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by VictorBorun » Mon Sep 02, 2024 9:40 am

AVAO wrote: Sun Sep 01, 2024 7:51 pm
Click to view full size image 1 or image 2
Bonus: The stem of the rose Credit: NASA/ESA (HERSCHEL)
far infrared?
The wavelengths that Herschel Space Observatory registered were 55 to 672 μm

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by AVAO » Sun Sep 01, 2024 7:51 pm

VictorBorun wrote: Tue Aug 20, 2024 2:36 pm
AVAO wrote: Mon Aug 19, 2024 4:38 am
APOD Robot wrote: Mon Aug 19, 2024 4:06 am Image IC 5146: The Cocoon Nebula

Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide. Soaring high in northern summer night skies, it's located some 4,000 light years away toward the constellation of the Swan (Cygnus). Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star found near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. A 48-hour long integration resulted in this exceptionally deep color view tracing tantalizing features within and surrounding the dusty stellar nursery.
<< Previous APOD This Day in APOD Next APOD >>

Beautiful cosmic rose - also in infrared!

Original data: NASA/ESA (SST) jac berne ( flickr)
IC 5146-The Cocoon Nebula-.jpgIC 5146-The Cocoon Nebula.jpg
...
Click to view full size image 1 or image 2
ThanX Victor!
Click to view full size image 1 or image 2
Bonus: The stem of the rose Credit: NASA/ESA (HERSCHEL)

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by VictorBorun » Tue Aug 20, 2024 2:36 pm

AVAO wrote: Mon Aug 19, 2024 4:38 am
APOD Robot wrote: Mon Aug 19, 2024 4:06 am Image IC 5146: The Cocoon Nebula

Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide. Soaring high in northern summer night skies, it's located some 4,000 light years away toward the constellation of the Swan (Cygnus). Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star found near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. A 48-hour long integration resulted in this exceptionally deep color view tracing tantalizing features within and surrounding the dusty stellar nursery.
<< Previous APOD This Day in APOD Next APOD >>

Beautiful cosmic rose - also in infrared!

Original data: NASA/ESA (SST) jac berne ( flickr)
IC 5146-The Cocoon Nebula-.jpg
IC 5146-The Cocoon Nebula.jpg
...
Click to view full size image 1 or image 2

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by Christian G. » Tue Aug 20, 2024 11:46 am

AVAO wrote: Mon Aug 19, 2024 4:38 am Beautiful cosmic rose - also in infrared!

Original data: NASA/ESA (SST) jac berne ( flickr)
Nice! You don't quite know a nebula until you've seen it in infrared!

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by AVAO » Mon Aug 19, 2024 6:56 pm

Chris Peterson wrote: Mon Aug 19, 2024 6:24 pm
AVAO wrote: Mon Aug 19, 2024 6:13 pm
Chris Peterson wrote: Mon Aug 19, 2024 1:52 pm

Most certainly, the nebula is being ionized by the output of many stars. If the BD+46 3474 system went away, we'd still observe a distinct H II region here.
Well, basically I would still agree with Ann, because of the paper "The Cocoon Nebula and its ionizing star: do stellar and nebular abundances agree?" [size=65]https://www.researchgate.net/ ... ree[/size]

The Cocoon nebula (IC 5146), a close-by Galactic H ii region ionized by a narrow line B0.5 V single star (BD+46 3474),...
The Cocoon nebula and its ionizing star, located at a distance of 800±80 pc, have a very similar chemical composition as
the Orion nebula and other B-type stars in the solar vicinity.

But the central region of the nebula actually contains about 30 relatively strong X-ray sources (cyan). These often correlate with O and B stars and are also visible in the IR. However, in contrast to the central stars of the Trifid Nebula, the fact that BD+46 3474 himself (green) is invisible even in X-ray is confusing me.

The Universe is ionized... and it is ionized by the radiation of every star, even little brown ones. It would be perfectly reasonable to say that the strongest source of ionizing radiation in the Cocoon is that one star, but all the same, if that star went away there's still plenty of energy to produce a significant (if much fainter) H II nebula.
ThanX Chris. With that I can basically agree.

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by Chris Peterson » Mon Aug 19, 2024 6:24 pm

AVAO wrote: Mon Aug 19, 2024 6:13 pm
Chris Peterson wrote: Mon Aug 19, 2024 1:52 pm
Ann wrote: Mon Aug 19, 2024 6:06 am


That's not correct! The Cocoon nebula is not ionized by young hot stars but by one young hot star, BD+46 3474, of spectral class B1V! This means that the Cocoon Nebula glows red even though it it not being ionized by even a single O-type star, and not even a single star of spectral class B0, but by a star of spectral class B1V and a number of smaller stars surrounding it (thanks, Jac, for the great picture you provided!).
Most certainly, the nebula is being ionized by the output of many stars. If the BD+46 3474 system went away, we'd still observe a distinct H II region here.
Well, basically I would still agree with Ann, because of the paper "The Cocoon Nebula and its ionizing star: do stellar and nebular abundances agree?" [size=65]https://www.researchgate.net/ ... ree[/size]

The Cocoon nebula (IC 5146), a close-by Galactic H ii region ionized by a narrow line B0.5 V single star (BD+46 3474),...
The Cocoon nebula and its ionizing star, located at a distance of 800±80 pc, have a very similar chemical composition as
the Orion nebula and other B-type stars in the solar vicinity.

But the central region of the nebula actually contains about 30 relatively strong X-ray sources (cyan). These often correlate with O and B stars and are also visible in the IR. However, in contrast to the central stars of the Trifid Nebula, the fact that BD+46 3474 himself (green) is invisible even in X-ray is confusing me.

The Universe is ionized... and it is ionized by the radiation of every star, even little brown ones. It would be perfectly reasonable to say that the strongest source of ionizing radiation in the Cocoon is that one star, but all the same, if that star went away there's still plenty of energy to produce a significant (if much fainter) H II nebula.

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by AVAO » Mon Aug 19, 2024 6:13 pm

Chris Peterson wrote: Mon Aug 19, 2024 1:52 pm
Ann wrote: Mon Aug 19, 2024 6:06 am
APOD Robot wrote:

Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud.
That's not correct! The Cocoon nebula is not ionized by young hot stars but by one young hot star, BD+46 3474, of spectral class B1V! This means that the Cocoon Nebula glows red even though it it not being ionized by even a single O-type star, and not even a single star of spectral class B0, but by a star of spectral class B1V and a number of smaller stars surrounding it (thanks, Jac, for the great picture you provided!).
Most certainly, the nebula is being ionized by the output of many stars. If the BD+46 3474 system went away, we'd still observe a distinct H II region here.
Well, basically I would still agree with Ann, because of the paper "The Cocoon Nebula and its ionizing star: do stellar and nebular abundances agree?" [size=65]https://www.researchgate.net/ ... ree[/size]

The Cocoon nebula (IC 5146), a close-by Galactic H ii region ionized by a narrow line B0.5 V single star (BD+46 3474),...
The Cocoon nebula and its ionizing star, located at a distance of 800±80 pc, have a very similar chemical composition as
the Orion nebula and other B-type stars in the solar vicinity.

But the central region of the nebula actually contains about 30 relatively strong X-ray sources (cyan). These often correlate with O and B stars and are also visible in the IR. However, in contrast to the central stars of the Trifid Nebula, the fact that BD+46 3474 himself (green) is invisible even in X-ray is confusing me.

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by Chris Peterson » Mon Aug 19, 2024 1:52 pm

Ann wrote: Mon Aug 19, 2024 6:06 am
APOD Robot wrote:

Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud.
That's not correct! The Cocoon nebula is not ionized by young hot stars but by one young hot star, BD+46 3474, of spectral class B1V! This means that the Cocoon Nebula glows red even though it it not being ionized by even a single O-type star, and not even a single star of spectral class B0, but by a star of spectral class B1V and a number of smaller stars surrounding it (thanks, Jac, for the great picture you provided!).
Most certainly, the nebula is being ionized by the output of many stars. If the BD+46 3474 system went away, we'd still observe a distinct H II region here.

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by Ann » Mon Aug 19, 2024 6:06 am

My gut reaction when I first saw this APOD, before my conscious thoughts and intellectual judgement had caught up with my extremely deep-seated emotional reaction to aesthetics, was, Wow, that's a lovely portrait of the Trifid Nebula!



But of course the APOD is not the Trifid Nebula but the Cocoon Nebula! 🌸 What a wonderful shade of magenta it is, too! :D

APOD Robot wrote:

Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud.
That's not correct! The Cocoon nebula is not ionized by young hot stars but by one young hot star, BD+46 3474, of spectral class B1V! This means that the Cocoon Nebula glows red even though it it not being ionized by even a single O-type star, and not even a single star of spectral class B0, but by a star of spectral class B1V and a number of smaller stars surrounding it (thanks, Jac, for the great picture you provided!).


If we compare the Cocoon Nebula with the Trifid Nebula, we can see that the Trifid Nebula is powered by a star of spectral class O7.5V. That means that the Trifid Nebula central star, HD 164492, is almost certainly producing several times more ultraviolet (let alone far ultraviolet) photons than the central star of the Cocoon nebula. We therefore have good reasons to believe that the Trifid Nebula is bigger (and probably brighter) than the Cocoon Nebula.


Wikipedia has provided an interesting list of typical properties of stars of spectral class B. According to this list, a star of spectral class B1V has a typical mass of 11 solar masses and a typical temperature of 26,000 K. But according to another Wikipedia entry, BD+46 3474 has an estimated mass of 14±4 solar masses, so it might be a bit more massive than what is "typical". Oh well.

(By contrast, a star of spectral class O7.5V may be at least 25 solar masses, and its temperature may be close to 40,000 K.)

Anyway, my point is this: I don't know of any other emission nebula with an NGC or IC designation that is powered just by a single star of spectral class B1!


All right, some ionization is also provided by the hue and cry of large numbers of angry little star babies in the process of being born around their big sibling BD+46 3474.


Oh, and by the way: That blue little nebula near bottom of the APOD is probably vdB 147 (in which case north is not up in the APOD):


The reason I wanted to call your attention to vdB 147 is that we do have access to the Gaia parallax of the central star of this nebula, BD+46 3471, and the Gaia parallax puts this star and its nebula at a distance of some 2,500 light-years. By contrast, there exists no Gaia parallax for the central star of the Cocoon Nebula. But if we assume that the Cocoon Nebula and the small reflection nebula vdB 147 are at similar distances from us - they do look like they could be connected - then the Cocoon Nebula is a lot closer to us than 4,000 light-years.

But of course it is possible that vdB 147 is a foreground object.

Ann

Re: APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by AVAO » Mon Aug 19, 2024 4:38 am

APOD Robot wrote: Mon Aug 19, 2024 4:06 am Image IC 5146: The Cocoon Nebula

Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide. Soaring high in northern summer night skies, it's located some 4,000 light years away toward the constellation of the Swan (Cygnus). Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star found near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. A 48-hour long integration resulted in this exceptionally deep color view tracing tantalizing features within and surrounding the dusty stellar nursery.
<< Previous APOD This Day in APOD Next APOD >>

Beautiful cosmic rose - also in infrared!

Original data: NASA/ESA (SST) jac berne ( flickr)

APOD: IC 5146: The Cocoon Nebula (2024 Aug 19)

by APOD Robot » Mon Aug 19, 2024 4:06 am

Image IC 5146: The Cocoon Nebula

Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide. Soaring high in northern summer night skies, it's located some 4,000 light years away toward the constellation of the Swan (Cygnus). Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star found near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. A 48-hour long integration resulted in this exceptionally deep color view tracing tantalizing features within and surrounding the dusty stellar nursery.

<< Previous APOD This Day in APOD Next APOD >>

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