APOD: M27: The Dumbbell Nebula (2023 May 30)

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APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by APOD Robot » Tue May 30, 2023 4:07 am

Image M27: The Dumbbell Nebula

Explanation: Is this what will become of our Sun? Quite possibly. The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, one of the brightest planetary nebulae on the sky and visible with binoculars toward the constellation of the Fox (Vulpecula). It takes light about 1000 years to reach us from M27, featured here in colors emitted by sulfur (red), hydrogen (green) and oxygen (blue). We now know that in about 6 billion years, our Sun will shed its outer gases into a planetary nebula like M27, while its remaining center will become an X-ray hot white dwarf star. Understanding the physics and significance of M27 was well beyond 18th century science, though. Even today, many things remain mysterious about planetary nebulas, including how their intricate shapes are created.

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Rauf » Tue May 30, 2023 5:09 am

Beautiful picture :ssmile: but why is there a rift on it's halo?
Maybe that part is blocked by something and doesn't get the energy it needs to be ionized, or maybe there is nothing to be ionized and glow at all?

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Ann » Tue May 30, 2023 6:09 am

Rauf wrote: Tue May 30, 2023 5:09 am Beautiful picture :ssmile: but why is there a rift on it's halo?
Maybe that part is blocked by something and doesn't get the energy it needs to be ionized, or maybe there is nothing to be ionized and glow at all?
Well, planetary nebulas are not my forte (at all). Also, the choice of mapped colors for this image doesn't necessarily agree with me.

But, regarding your questions, many planetary nebulas (and perhaps M27 in particular) show signs of two jets emanating from the central white dwarf star (from the poles of the white dwarf). In the APOD, you can see the trail of the jets running from 11 o'clock to 5 o'clock. The jets may have bisected the halo of the planetary.

But we need more than jets to explain all the dark streaks in the halo. There is an inner "bubble" in the planetary surrounded by a dusty "border". We have every reason to believe that the stellar wind, the level of ionization and other parameters are different inside this bubble than outside it. That means that things may happen at the border. There could, for example, be dust production there.


On the Earth, anticrepuscular rays (long straight dark streaks across the sky) are created because clouds are partly but not completely blocking light from the Sun. It could be that the dusty border around the inner bubble of M27 blocks light from the white dwarf in certain places and lets it through in other places, creating the dark streaks that we see in the halo.

But I'm just guessing.

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by MarkEt » Tue May 30, 2023 7:58 am

Seems the outer layers are blown out by the initial collapse, then depending on the mass involved you either get the white dwarf or supernova and black hole following it

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Chris Peterson » Tue May 30, 2023 1:21 pm

MarkEt wrote: Tue May 30, 2023 7:58 am Seems the outer layers are blown out by the initial collapse, then depending on the mass involved you either get the white dwarf or supernova and black hole following it
Stars that produce planetary nebulas are not massive enough to end in supernovas or to become either neutron stars or black holes. In the last few millennia of their fusing existence very high stellar winds blow off much of their mass, producing what we see as planetary nebulas, typically ionized by the very hot end stage of their fusion or their final stage as a white dwarf.
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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by MarkEt » Tue May 30, 2023 1:47 pm

Yes, Chris, thanks for reiterating my point.

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Rauf » Tue May 30, 2023 4:41 pm

Ann wrote: Tue May 30, 2023 6:09 am
Rauf wrote: Tue May 30, 2023 5:09 am Beautiful picture :ssmile: but why is there a rift on it's halo?
Maybe that part is blocked by something and doesn't get the energy it needs to be ionized, or maybe there is nothing to be ionized and glow at all?
Well, planetary nebulas are not my forte (at all). Also, the choice of mapped colors for this image doesn't necessarily agree with me.

But, regarding your questions, many planetary nebulas (and perhaps M27 in particular) show signs of two jets emanating from the central white dwarf star (from the poles of the white dwarf). In the APOD, you can see the trail of the jets running from 11 o'clock to 5 o'clock. The jets may have bisected the halo of the planetary.

But we need more than jets to explain all the dark streaks in the halo. There is an inner "bubble" in the planetary surrounded by a dusty "border". We have every reason to believe that the stellar wind, the level of ionization and other parameters are different inside this bubble than outside it. That means that things may happen at the border. There could, for example, be dust production there.


On the Earth, anticrepuscular rays (long straight dark streaks across the sky) are created because clouds are partly but not completely blocking light from the Sun. It could be that the dusty border around the inner bubble of M27 blocks light from the white dwarf in certain places and lets it through in other places, creating the dark streaks that we see in the halo.

But I'm just guessing.

Ann
Thanks Ann. The dark steak on 5 o'clock is the largest and follows the sulfur emissions in the inner bubble. Maybe it's got something to do with that?
But.. I have no idea how it works.

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Ann » Tue May 30, 2023 4:55 pm

Rauf wrote: Tue May 30, 2023 4:41 pm
Ann wrote: Tue May 30, 2023 6:09 am
Rauf wrote: Tue May 30, 2023 5:09 am Beautiful picture :ssmile: but why is there a rift on it's halo?
Maybe that part is blocked by something and doesn't get the energy it needs to be ionized, or maybe there is nothing to be ionized and glow at all?
Well, planetary nebulas are not my forte (at all). Also, the choice of mapped colors for this image doesn't necessarily agree with me.

But, regarding your questions, many planetary nebulas (and perhaps M27 in particular) show signs of two jets emanating from the central white dwarf star (from the poles of the white dwarf). In the APOD, you can see the trail of the jets running from 11 o'clock to 5 o'clock. The jets may have bisected the halo of the planetary.

But we need more than jets to explain all the dark streaks in the halo. There is an inner "bubble" in the planetary surrounded by a dusty "border". We have every reason to believe that the stellar wind, the level of ionization and other parameters are different inside this bubble than outside it. That means that things may happen at the border. There could, for example, be dust production there.


On the Earth, anticrepuscular rays (long straight dark streaks across the sky) are created because clouds are partly but not completely blocking light from the Sun. It could be that the dusty border around the inner bubble of M27 blocks light from the white dwarf in certain places and lets it through in other places, creating the dark streaks that we see in the halo.

But I'm just guessing.

Ann
Thanks Ann. The dark steak on 5 o'clock is the largest and follows the sulfur emissions in the inner bubble. Maybe it's got something to do with that?
But.. I have no idea how it works.
And I was sort of hoping Chris would chime in. But he hasn't. :wink:

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Chris Peterson » Tue May 30, 2023 4:55 pm

Rauf wrote: Tue May 30, 2023 4:41 pm Thanks Ann. The dark steak on 5 o'clock is the largest and follows the sulfur emissions in the inner bubble. Maybe it's got something to do with that?
But.. I have no idea how it works.
The orange region is hydrogen, not sulfur (really, it is hydrogen slightly contaminated with sulfur). This is important because hydrogen is the dominant element here, and contributes most of the mass. Which also means it has the most gravitational effect, which is why we typically see a close association between hydrogen concentrations and dust concentrations. In these wavelengths the visible emission of the hydrogen makes it very difficult to see dust, but it's likely there, and when radially distributed can generate shadows in the outer region analogous to the crepuscular rays Ann brings up.

Also worth keeping in mind is that the intensity scale on today's APOD is extremely nonlinear. Below is a much less stretched version, and you can see just how much dimmer that outer region is than the inner. Today's image is processed to emphasize the much, much more nebulous outer region (which is fine, of course), but that also makes the shadows (if they are shadows) look much more dramatic than they actually are.
_
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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Chris Peterson » Tue May 30, 2023 4:56 pm

Ann wrote: Tue May 30, 2023 4:55 pm And I was sort of hoping Chris would chime in. But he hasn't. :wink:

Ann
Ding ding.
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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Ann » Tue May 30, 2023 4:59 pm

Chris Peterson wrote: Tue May 30, 2023 4:56 pm
Ann wrote: Tue May 30, 2023 4:55 pm And I was sort of hoping Chris would chime in. But he hasn't. :wink:

Ann
Ding ding.
Thanks Chris, I feel "auditorily enlightened".

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Rauf » Tue May 30, 2023 5:12 pm

Chris Peterson wrote: Tue May 30, 2023 4:56 pm
Ann wrote: Tue May 30, 2023 4:55 pm And I was sort of hoping Chris would chime in. But he hasn't. :wink:

Ann
Ding ding.
Thanks a lot for your answers. I am much less confused now :ssmile:
Time to stop thinking a little and let the beauty of the picture sink me in :ssmile:

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Ann » Tue May 30, 2023 5:36 pm

Chris Peterson wrote: Tue May 30, 2023 4:55 pm
Rauf wrote: Tue May 30, 2023 4:41 pm Thanks Ann. The dark steak on 5 o'clock is the largest and follows the sulfur emissions in the inner bubble. Maybe it's got something to do with that?
But.. I have no idea how it works.
The orange region is hydrogen, not sulfur (really, it is hydrogen slightly contaminated with sulfur). This is important because hydrogen is the dominant element here, and contributes most of the mass. Which also means it has the most gravitational effect, which is why we typically see a close association between hydrogen concentrations and dust concentrations. In these wavelengths the visible emission of the hydrogen makes it very difficult to see dust, but it's likely there, and when radially distributed can generate shadows in the outer region analogous to the crepuscular rays Ann brings up.

Also worth keeping in mind is that the intensity scale on today's APOD is extremely nonlinear. Below is a much less stretched version, and you can see just how much dimmer that outer region is than the inner. Today's image is processed to emphasize the much, much more nebulous outer region (which is fine, of course), but that also makes the shadows (if they are shadows) look much more dramatic than they actually are.
_
Thanks, Chris. You did chime in for real.

That's your own picture of the Dumbbell Nebula, I presume?

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Christian G. » Tue May 30, 2023 5:38 pm

Chris Peterson wrote: Tue May 30, 2023 1:21 pm
MarkEt wrote: Tue May 30, 2023 7:58 am Seems the outer layers are blown out by the initial collapse, then depending on the mass involved you either get the white dwarf or supernova and black hole following it
Stars that produce planetary nebulas are not massive enough to end in supernovas or to become either neutron stars or black holes. In the last few millennia of their fusing existence very high stellar winds blow off much of their mass, producing what we see as planetary nebulas, typically ionized by the very hot end stage of their fusion or their final stage as a white dwarf.
Planetary nebulae descriptions often leave something vague about the process, I find, namely that the star "sheds" its outer layers. What does shed mean? The layers just detach and float away? What is the actual process? So here you bring a much appreciated precision: stellar winds blow off the layers. So is that the process? While supernovae remnants are formed by a bounce-off of layers, planetary nebulae are formed by winds blowing away layers? (winds that are intensifying as the star contracts maybe?)

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Chris Peterson » Tue May 30, 2023 6:24 pm

Chris Alex wrote: Tue May 30, 2023 5:38 pm
Chris Peterson wrote: Tue May 30, 2023 1:21 pm
MarkEt wrote: Tue May 30, 2023 7:58 am Seems the outer layers are blown out by the initial collapse, then depending on the mass involved you either get the white dwarf or supernova and black hole following it
Stars that produce planetary nebulas are not massive enough to end in supernovas or to become either neutron stars or black holes. In the last few millennia of their fusing existence very high stellar winds blow off much of their mass, producing what we see as planetary nebulas, typically ionized by the very hot end stage of their fusion or their final stage as a white dwarf.
Planetary nebulae descriptions often leave something vague about the process, I find, namely that the star "sheds" its outer layers. What does shed mean? The layers just detach and float away? What is the actual process? So here you bring a much appreciated precision: stellar winds blow off the layers. So is that the process? While supernovae remnants are formed by a bounce-off of layers, planetary nebulae are formed by winds blowing away layers? (winds that are intensifying as the star contracts maybe?)
Yes, that's the current understanding. Just plain old solar wind on steroids. The Sun sheds mass via solar wind, as well... just at a much lower rate than it will at the end of its life.
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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by VictorBorun » Tue May 30, 2023 7:01 pm

Ann wrote: Tue May 30, 2023 6:09 am
Rauf wrote: Tue May 30, 2023 5:09 am Beautiful picture :ssmile: but why is there a rift on it's halo?
Maybe that part is blocked by something and doesn't get the energy it needs to be ionized, or maybe there is nothing to be ionized and glow at all?
On the Earth, anticrepuscular rays (long straight dark streaks across the sky) are created because clouds are partly but not completely blocking light from the Sun. It could be that the dusty border around the inner bubble of M27 blocks light from the white dwarf in certain places and lets it through in other places, creating the dark streaks that we see in the halo.
But I'm just guessing.
Ann
There may be even more similarity. The rays that span out in our perspective are in fact almost parallel and just their ends are much closer to us than their starting parts.
The Dumbbell rays may be scattering in dust say 500 to 1000 ly distant and span out in our 2D picture because of the perspective
Click to view full size image 1 or image 2
APOD M27=The Dumbbell Nebula (2023 May 30)..jpg
APOD M27=The Dumbbell Nebula (2023 May 30) 2.jpg
...
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Last edited by VictorBorun on Tue May 30, 2023 7:29 pm, edited 1 time in total.

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by VictorBorun » Tue May 30, 2023 7:27 pm

Crepuscular_Rays_Panorama_HD_-_Copy hdr.jpg
It is a problem to show (anti)crepuscular rays in the same pic as the main lamp.
For a sunset scene we can use varying exposure, sort of HDR
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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Ann » Tue May 30, 2023 7:35 pm

Chris Alex wrote: Tue May 30, 2023 5:38 pm
Chris Peterson wrote: Tue May 30, 2023 1:21 pm
MarkEt wrote: Tue May 30, 2023 7:58 am Seems the outer layers are blown out by the initial collapse, then depending on the mass involved you either get the white dwarf or supernova and black hole following it
Stars that produce planetary nebulas are not massive enough to end in supernovas or to become either neutron stars or black holes. In the last few millennia of their fusing existence very high stellar winds blow off much of their mass, producing what we see as planetary nebulas, typically ionized by the very hot end stage of their fusion or their final stage as a white dwarf.
Planetary nebulae descriptions often leave something vague about the process, I find, namely that the star "sheds" its outer layers. What does shed mean? The layers just detach and float away? What is the actual process? So here you bring a much appreciated precision: stellar winds blow off the layers. So is that the process? While supernovae remnants are formed by a bounce-off of layers, planetary nebulae are formed by winds blowing away layers? (winds that are intensifying as the star contracts maybe?)
I think - think, mind you, and I'm too lazy to google - that sunlike stars that are at the end of their lives have two fusion processes going. In their core, these stars fuse helium into oxygen and carbon. in a shell around their core, they fuse hydrogen into helium.

But here's the deal: I think that these fusion processes turn on and off, and when one fusion process is on, the other is on hold. This injects spurts of energy into the system instead of creating a "smooth flow of energy" as in the Sun. On-off, on-off, on-off, on-off!!!

I think this creates an imbalance in the star that causes the star to lose its outer layers. I think that sunlike stars typically lose their outer layers in several stages. Also, when the star has lost a great deal of its outer layers, the stellar wind will get stronger. The reason for this would be that there used to be a perfect balance between the outward-directed energy generated in the star's core and the inward-directed pressure caused by the entire mass of the star. But when the star has shrugged off a considerable amount of its mass, and the energy generated in the core is still the same (or actually greater), then there will be a pretty furious wind blowing from the star's core, and the mass loss will proceed even faster.

Do chime in here, Chris. Ding ding!

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Chris Peterson » Tue May 30, 2023 7:53 pm

Ann wrote: Tue May 30, 2023 7:35 pm
Chris Alex wrote: Tue May 30, 2023 5:38 pm
Chris Peterson wrote: Tue May 30, 2023 1:21 pm

Stars that produce planetary nebulas are not massive enough to end in supernovas or to become either neutron stars or black holes. In the last few millennia of their fusing existence very high stellar winds blow off much of their mass, producing what we see as planetary nebulas, typically ionized by the very hot end stage of their fusion or their final stage as a white dwarf.
Planetary nebulae descriptions often leave something vague about the process, I find, namely that the star "sheds" its outer layers. What does shed mean? The layers just detach and float away? What is the actual process? So here you bring a much appreciated precision: stellar winds blow off the layers. So is that the process? While supernovae remnants are formed by a bounce-off of layers, planetary nebulae are formed by winds blowing away layers? (winds that are intensifying as the star contracts maybe?)
I think - think, mind you, and I'm too lazy to google - that sunlike stars that are at the end of their lives have two fusion processes going. In their core, these stars fuse helium into oxygen and carbon. in a shell around their core, they fuse hydrogen into helium.

But here's the deal: I think that these fusion processes turn on and off, and when one fusion process is on, the other is on hold. This injects spurts of energy into the system instead of creating a "smooth flow of energy" as in the Sun. On-off, on-off, on-off, on-off!!!

I think this creates an imbalance in the star that causes the star to lose its outer layers. I think that sunlike stars typically lose their outer layers in several stages. Also, when the star has lost a great deal of its outer layers, the stellar wind will get stronger. The reason for this would be that there used to be a perfect balance between the outward-directed energy generated in the star's core and the inward-directed pressure caused by the entire mass of the star. But when the star has shrugged off a considerable amount of its mass, and the energy generated in the core is still the same (or actually greater), then there will be a pretty furious wind blowing from the star's core, and the mass loss will proceed even faster.

Do chime in here, Chris. Ding ding!

Ann
Not really my area of expertise. As I understand it, the stellar wind from stars like the Sun consists of a plasma of charged particles, mainly electrons and protons, which are accelerated out of the very hot corona to greater than the solar escape velocity by some sort of magnetic processes within the star. The stellar wind from end-stage low mass stars is caused by radiation pressure on the dust that accumulates in the upper atmosphere. It is much lower speed but carries away a lot more mass. So really, two very different processes that go by the same name. The escape velocity at the top of the atmosphere of a red giant is a lot less than at the top of the atmosphere of a G-class star like the Sun.
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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by AVAO » Tue May 30, 2023 8:36 pm

Ann wrote: Tue May 30, 2023 6:09 am
Rauf wrote: Tue May 30, 2023 5:09 am Beautiful picture :ssmile: but why is there a rift on it's halo?
Maybe that part is blocked by something and doesn't get the energy it needs to be ionized, or maybe there is nothing to be ionized and glow at all?
Well, planetary nebulas are not my forte (at all). Also, the choice of mapped colors for this image doesn't necessarily agree with me.

But, regarding your questions, many planetary nebulas (and perhaps M27 in particular) show signs of two jets emanating from the central white dwarf star (from the poles of the white dwarf). In the APOD, you can see the trail of the jets running from 11 o'clock to 5 o'clock. The jets may have bisected the halo of the planetary....
Ann
ThanX Ann

I also see two "cones of light" in the image, with the 4 o'clock ray pointing towards us and the 10 o'clock ray pointing away from us.
The beam away from us in the direction of 10 o'clock illuminates the "back" dust (left side) in point form (pink) almost exactly. On the other hand, part of the ray in our direction is strongly absorbed partially by a dark cloud, which creates the dark "shadow ray". All in all, the two illuminated bipolar jets of dust and gas (gas tubes in blue) move clockwise, I think. This is my humble attempt at an explanation.-)

Image
biggger:https://live.staticflickr.com/65535/529 ... e952_o.jpg
..collage from many sources to illustrate my concept...
[/quote]
Last edited by AVAO on Tue May 30, 2023 9:34 pm, edited 4 times in total.

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Re: APOD: M27: The Dumbbell Nebula (2023 May 30)

Post by Pcos » Tue May 30, 2023 8:50 pm

Hi Folks,

This is my image. When I took it, I was amazed by how very different the Ha, O3, and S2 images were. The S2 looked similar in shape to what I would see with broadband exposure. The Ha image was very detailed and lacey. The O3 image was very smooth and looked like the wings of an angel. In fact, I would say that the three filter images are the most different from one another than on any other narrowband image that I have taken.

When combining these images, I had a lot of choices - artistically - on how to do that, and I created many versions but ultimately went with one where I created a synthetic luminance channel by combining the Ha and O3 signals and then used a modified Hubble Palette for the color rendering. I was happy with this image, and it ultimately was published in the May 2022 issue of Astronomy Magazine

While processing, I saw a considerable amount of detail in the faint outer shell that was not brought out well in my original image. So while the smoke plume from the Alberta Widfires shut down my Sky, I decided to reprocess my original data - to highlight the faint detail that was in the Outer shells.

All-in-all, I found M27 to be a fascinating target!

Thanks,
Pat