APOD: Inside the Flame Nebula (2019 Nov 02)

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APOD: Inside the Flame Nebula (2019 Nov 02)

Post by APOD Robot » Sat Nov 02, 2019 4:07 am

Image Inside the Flame Nebula

Explanation: The Flame Nebula stands out in this optical image of the dusty, crowded star forming regions toward Orion's belt, a mere 1,400 light-years away. X-ray data from the Chandra Observatory and infrared images from the Spitzer Space Telescope can take you inside the glowing gas and obscuring dust clouds though. Swiping your cursor (or clicking the image) will reveal many stars of the recently formed, embedded cluster NGC 2024, ranging in age from 200,000 years to 1.5 million years young. The X-ray/infrared composite image overlay spans about 15 light-years across the Flame's center. The X-ray/infrared data also indicate that the youngest stars are concentrated near the middle of the Flame Nebula cluster. That's the opposite of the simplest models of star formation for the stellar nursery that predict star formation begins in the denser center of a molecular cloud core. The result requires a more complex model; perhaps star formation continues longer in the center, or older stars are ejected from the center due to subcluster mergers.

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by Ann » Sat Nov 02, 2019 6:09 am

Interesting APOD! Thanks for the mouseover!

Unsurprisingly, the Flame Nebula young star cluster is mostly found under the thick dark dust lane that is so obvious in visible light images.

I have wondered for a long time what kind of stars are being born inside the Flame Nebula. Low-mass stars, to be sure. Are there any high-mass stars there, too?

All the X-ray sources look equally sized and "small", which is why I think that the Flame Nebula cluster might be a low-mass one. On the other hand, the cluster is possibly "rich". There are certainly at least 40 little purple sources in the middle of the Flame Nebula. It is my impression that "rich" clusters typically contain at least one, or maybe a few, high-mass stars.

Does anyone know if there are any young whoppers among the baby stars in the Flame Nebula?

Ann
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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by neufer » Sat Nov 02, 2019 11:59 am

https://apod.nasa.gov/apod/ap101126.html wrote:
<<"Insta-Burger King" was founded in 1953 as a Jacksonville, Florida–based restaurant chain. The "Insta-Broiler" worked by cooking 12 burger patties in a wire basket, allowing the patties to be cooked from both sides simultaneously.

In 1954, David Edgerton and James McLamore purchased the company and renamed it "Burger King" since they had decided to switch the "Insta-Broiler" to an improved "Flame Broiler". Designed by the two the "Flame Broiler" featured stationary burners that cooked the meat on a moving chain. In 1957, the "Flame Broiled Whopper" became the first major addition to the menu, and it has become Burger King's signature product since.>>
Ann wrote:
Sat Nov 02, 2019 6:09 am

Does anyone know if there are any young whoppers among the baby stars in the Flame Nebula?
  • There seems to be some debate on this issue:
https://arxiv.org/abs/astro-ph/0303029 wrote:
Identification of the ionizing source of NGC 2024 (2003 paper)

<<We propose the late-O, early-B star IRS2b as the ionizing source of the Flame Nebula (NGC 2024). It has been clear that such a hot, massive star must be present in this heavily obscured region, and now it has been identified. New near-infrared photometry shows that IRS2b is the most luminous and hottest star in the young star cluster embedded in the center of NGC 2024. The near-infrared observations (5' x 5') cover ~90 % of the HII region detected in radio continuum radiation, making the probability very low that the ionizing star is not present in the field. A K-band spectrum of IRS2b obtained with ISAAC on the Very Large Telescope indicates that the spectral type of IRS2b is in the range O8V - B2V. Additional arguments indicate that its spectral type is likely closer to O8 than to B2. The corresponding amount of ionizing radiation is consistent with published radio continuum and recombination line observations.>>
https://en.wikipedia.org/wiki/Flame_Nebula wrote:
<<The Flame Nebula, designated as NGC 2024 and Sh2-277, is an emission nebula in the constellation Orion.

The bright star Alnitak (ζ Ori), the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the Flame and this knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.

At the center of the Flame Nebula is a cluster of newly formed stars, 86% of which have circumstellar disks. X-ray observations by the Chandra X-ray Observatory show several hundred young stars, out of an estimated population of 800 stars. X-ray and infrared images indicate that the youngest stars are concentrated near the center of the cluster.>>
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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by orin stepanek » Sat Nov 02, 2019 1:25 pm

Wow; the horsehead is hardly noticeable on the insett! :shock:
flame_optical_overlay.jpg
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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by neufer » Sat Nov 02, 2019 2:45 pm

orin stepanek wrote:
Sat Nov 02, 2019 1:25 pm

Wow; the horsehead is hardly noticeable on the insett! :shock:
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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by Ann » Sat Nov 02, 2019 2:51 pm

neufer wrote:
Sat Nov 02, 2019 11:59 am
https://en.wikipedia.org/wiki/Flame_Nebula wrote:
<<The Flame Nebula, designated as NGC 2024 and Sh2-277, is an emission nebula in the constellation Orion.

The bright star Alnitak (ζ Ori), the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the Flame and this knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.

At the center of the Flame Nebula is a cluster of newly formed stars, 86% of which have circumstellar disks. X-ray observations by the Chandra X-ray Observatory show several hundred young stars, out of an estimated population of 800 stars. X-ray and infrared images indicate that the youngest stars are concentrated near the center of the cluster.>>
The Horsehead and Flame nebula (left). Photo:
Antoine Grelin
The Flame nebula. Source:
X-ray: NASA/CXC/PSU/K.Getman, E.Feigelson, M.Kuhn & the MYStIX team;
Infrared: NASA/JPL-Caltech



















One of my objections to the idea of Alnitak being the main ionizing source of the Flame nebula is that the Flame nebula is yellowish in color, and clearly yellower than the Hα nebula making up the background for the Horsehead nebula. If both the Horsehead nebula background and the Flame nebula are emission nebulas ionized by external sources, why would one nebula be so much yellower than the other one?

The yellow color of the Flame nebula might be at least partly explained if we assume that the Flame nebula is a combined red emission and blue reflection nebula being dust-reddened from within. A pure red Hα nebula, by contrast, can't be reddened into a yellow color.

Another of my objections to the idea of Alnitak being the prime ionizing source of the Flame nebula is that the inner workings and structures of the Flame nebula are so symmetrical and so centered on the central inner cluster. By far most of the energy of this nebula seems to come from within, from the embedded cluster, and not from an outside source off to one side.

So I believe that Alnitak is playing second fiddle when it comes to ionizing the Flame.

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by neufer » Sat Nov 02, 2019 3:58 pm

Ann wrote:
Sat Nov 02, 2019 2:51 pm

One of my objections to the idea of Alnitak being the main ionizing source of the Flame nebula is that the Flame nebula is yellowish in color, and clearly yellower than the Hα nebula making up the background for the Horsehead nebula. If both the Horsehead nebula background and the Flame nebula are emission nebulas ionized by external sources, why would one nebula be so much yellower than the other one?

The yellow color of the Flame nebula might be at least partly explained if we assume that the Flame nebula is a combined red emission and blue reflection nebula being dust-reddened from within. A pure red Hα nebula, by contrast, can't be reddened into a yellow color.

Another of my objections to the idea of Alnitak being the prime ionizing source of the Flame nebula is that the inner workings and structures of the Flame nebula are so symmetrical and so centered on the central inner cluster. By far most of the energy of this nebula seems to come from within, from the embedded cluster, and not from an outside source off to one side.

So I believe that Alnitak is playing second fiddle when it comes to ionizing the Flame.
Click to play embedded YouTube video.
According to the Wikipedia data:
  • the Flame nebula is just 12 ly in diameter
    but lies ~90 ly behind Alnitak.
If this is true then:
  • 1) the Flame nebula should be relatively evenly illuminated by Alnitak and

    2) the Flame nebula's dust should reflect significantly Alnitak's blue light.
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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by BDanielMayfield » Sat Nov 02, 2019 8:26 pm

APOD Robot wrote:
Sat Nov 02, 2019 4:07 am
Explanation: ... The X-ray/infrared data also indicate that the youngest stars are concentrated near the middle of the Flame Nebula cluster. That's the opposite of the simplest models of star formation for the stellar nursery that predict star formation begins in the denser center of a molecular cloud core. The result requires a more complex model; perhaps star formation continues longer in the center, or older stars are ejected from the center due to subcluster mergers.
I'm wondering if strong stellar winds from newly formed stars on the periphery of this cluster could have compressed gas toward the center, resulting in the inverse of the typical center out sequence of star formation.
"Happy are the peaceable ... "

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by Ann » Sat Nov 02, 2019 9:01 pm

neufer wrote:
Sat Nov 02, 2019 3:58 pm
According to the Wikipedia data:
  • the Flame nebula is just 12 ly in diameter
    but lies ~90 ly behind Alnitak.
If this is true then:
  • 1) the Flame nebula should be relatively evenly illuminated by Alnitak and

    2) the Flame nebula's dust should reflect significantly Alnitak's blue light.
Ah, but the dust lanes of the Flame Nebula aren't blue!

The Horsehead and Flame nebula (left), with non-blue dust lanes.
Photo: Antoine Grelin
The Flaming Star Nebula, with blue dust lanes.
Photo: Russell Croman/science Photo Library



















Why would blue light from Alnitak reflected by the dust of the Flame nebula result in dark or light brown dust lanes?

In my opinion, little of the Flame Nebula is illuminated from the outside. The Flaming Star Nebula, by contrast, is a combined emission/reflection nebula ionized and illuminated by a single star, the hot blue and ultraviolet runaway star AE Aurigae. Dust lanes of the Flaming Star nebula do indeed look blue.

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by neufer » Sun Nov 03, 2019 11:53 am

Ann wrote:
Sat Nov 02, 2019 9:01 pm

In my opinion, little of the Flame Nebula is illuminated from the outside. The Flaming Star Nebula, by contrast, is a combined emission/reflection nebula ionized and illuminated by a single star, the hot blue and ultraviolet runaway star AE Aurigae. Dust lanes of the Flaming Star nebula do indeed look blue.
Well...I have plum run out of lame jokes here
(and you are ignoring them anyway)
so let's just go with these guys:

https://arxiv.org/abs/astro-ph/0303029
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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by Ann » Sun Nov 03, 2019 11:58 am

neufer wrote:
Sun Nov 03, 2019 11:53 am
Ann wrote:
Sat Nov 02, 2019 9:01 pm

In my opinion, little of the Flame Nebula is illuminated from the outside. The Flaming Star Nebula, by contrast, is a combined emission/reflection nebula ionized and illuminated by a single star, the hot blue and ultraviolet runaway star AE Aurigae. Dust lanes of the Flaming Star nebula do indeed look blue.
Well...I have plum run out of lame jokes here
(and you are ignoring them anyway)
so let's just go with these guys:

https://arxiv.org/abs/astro-ph/0303029
Thanks, Art! :D

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by Ann » Sun Nov 03, 2019 5:13 pm

neufer wrote:
Sun Nov 03, 2019 11:53 am

Well...I have plum run out of lame jokes here
(and you are ignoring them anyway)
so let's just go with these guys:

https://arxiv.org/abs/astro-ph/0303029
Well, I don't know about me ignoring your jokes: viewtopic.php?p=296577#p296577

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by neufer » Sun Nov 03, 2019 5:33 pm

Click to play embedded YouTube video.
Ann wrote:
Sun Nov 03, 2019 5:13 pm
neufer wrote:
Sun Nov 03, 2019 11:53 am

Well...I have plum run out of lame jokes here
(and you are ignoring them anyway)
so let's just go with these guys:

https://arxiv.org/abs/astro-ph/0303029
Well, I don't know about me ignoring your jokes:
viewtopic.php?p=296577#p296577
I specifically stipulated: my lame jokes HERE.
Art Neuendorffer

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Re: APOD: Inside the Flame Nebula (2019 Nov 02)

Post by Ann » Sun Nov 03, 2019 6:11 pm

neufer wrote:
Sun Nov 03, 2019 5:33 pm
Click to play embedded YouTube video.
Ann wrote:
Sun Nov 03, 2019 5:13 pm
neufer wrote:
Sun Nov 03, 2019 11:53 am

Well...I have plum run out of lame jokes here
(and you are ignoring them anyway)
so let's just go with these guys:

https://arxiv.org/abs/astro-ph/0303029
Well, I don't know about me ignoring your jokes:
viewtopic.php?p=296577#p296577
I specifically stipulated: my lame jokes HERE.
Well, Kermit and Fozzie the Bear were somewhat lame....

Gimme the two old geezers in their box any day! (Course, I kind of like the Swedish chef too, although I don't know why...)

Ann
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