APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

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APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by APOD Robot » Wed Nov 09, 2022 5:09 am

Image The Asymmetric Nebula Surrounding Wolf-Rayet Star 18

Explanation: Why does the nebula around the star WR-18 shine brighter on one side? Also known as NGC 3199, this active star and its surrounding nebula lie about 12,000 light-years away toward the nautical southern constellation of Carina. The featured deep image has been highly processed to bring out filamentary details of the glowing gas in the bubble-shaped nebula. The nebula is about 75 light-years across. Near the nebula's center is a Wolf-Rayet star, WR-18, which is a massive, hot, short-lived star that generates an intense and complex stellar wind. In fact, Wolf-Rayet stars are known to create nebulas with interesting shapes as their powerful winds sweep up surrounding interstellar material. In this case, the bright right edge was initially thought to indicate that a bow shock was being produced as the star plowed through a uniform medium, like a boat through water. Recent measurements and analyses, however, have shown the star is not moving quickly toward the bright edge. A more likely explanation has emerged that the material surrounding the star is not uniform, but clumped and denser near the bright edge.

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by AstroLux » Wed Nov 09, 2022 8:42 am

Unfortunately this image has been overprocessed so much that the actual data has been destroyed and the final image looks really bad.

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by madtom1999 » Wed Nov 09, 2022 8:50 am

Just wondering here - if a star has a very strong magnetic field then when it starts blasting itself out into the cosmos presumably the magnetic field is going to sort the ions and electrons in different directions possibly leading to the asymmetric nebula seen.

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Iksarfighter » Wed Nov 09, 2022 10:41 am

So it is not a Doppler effect ?
Last edited by Iksarfighter on Wed Nov 09, 2022 1:58 pm, edited 1 time in total.

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by De58te » Wed Nov 09, 2022 12:30 pm

If I may offer my not very scientific based theory. Perhaps the Wolf half side of the Wolf-Rayet star is facing the bright nebula. As you may know wolves are strong howlers so they likely produces strong howling solar winds. The Rayet side of the star like in the Russian language can be Nyet, Nyet in producing strong rays -yet!

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by VictorBorun » Wed Nov 09, 2022 1:21 pm

AstroLux wrote: Wed Nov 09, 2022 8:42 am Unfortunately this image has been overprocessed so much that the actual data has been destroyed and the final image looks really bad.
wait a second, gonna hang another image over
wr18 overlay.jpg
wr18_woronow_2048.jpg
...
here is the APOD from 2008 May 22 over this APOD
Click to view full size image 1 or image 2
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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by orin stepanek » Wed Nov 09, 2022 1:32 pm

wr18_woronow_960.jpg
Interesting photo; can someone locate the star?
https://image.shutterstock.com/image-ph ... 814405.jpg Awesome looking kitty!
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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Chris Peterson » Wed Nov 09, 2022 2:04 pm

AstroLux wrote: Wed Nov 09, 2022 8:42 am Unfortunately this image has been overprocessed so much that the actual data has been destroyed and the final image looks really bad.
No, it has been heavily processed, with the intent of revealing specific structural detail, not to look "good". A completely normal and necessary process used by scientific imagers everywhere.
Chris

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by VictorBorun » Wed Nov 09, 2022 3:00 pm

orin stepanek wrote: Wed Nov 09, 2022 1:32 pm wr18_woronow_960.jpg
Interesting photo; can someone locate the star?
https://image.shutterstock.com/image-ph ... 814405.jpg Awesome looking kitty!
wait a second, I'm hanging over
wr18 overlay 2.jpg
...
wr 18 red ring hanging over this APOD
Click to view full size image 1 or image 2
They say this:
Figure 3. Color-composite image of NGC 3199 around WR 18. Red, green, and blue correspond to Sii, Oiii, and
the soft X-ray band (0.3–1.1 keV), respectively. All point-like sources have been cut out from the X-ray image except
WR 18 (see text for details). The position of WR 18 is shown with a red circle whilst other circles mark the positions
of the nerby Tycho-Gaia Astrometric Solution stars in the field of view. The black circle shows the position of the
BOV star CD − 57 ◦ 3120 (see Discussion). North is up, east to the left.
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Uncle Jeff

Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Uncle Jeff » Thu Nov 10, 2022 2:29 am

Instead of the WR star or its motion being asymmetrical, perhaps the surrounding gas/plasma is.

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by orin stepanek » Thu Nov 10, 2022 4:06 am

VictorBorun wrote: Wed Nov 09, 2022 3:00 pm
orin stepanek wrote: Wed Nov 09, 2022 1:32 pm wr18_woronow_960.jpg
Interesting photo; can someone locate the star?
https://image.shutterstock.com/image-ph ... 814405.jpg Awesome looking kitty!
wait a second, I'm hanging over
wr18 overlay 2.jpg
...
wr 18 red ring hanging over this APOD
Click to view full size image 1 or image 2
They say this:
Figure 3. Color-composite image of NGC 3199 around WR 18. Red, green, and blue correspond to Sii, Oiii, and
the soft X-ray band (0.3–1.1 keV), respectively. All point-like sources have been cut out from the X-ray image except
WR 18 (see text for details). The position of WR 18 is shown with a red circle whilst other circles mark the positions
of the nerby Tycho-Gaia Astrometric Solution stars in the field of view. The black circle shows the position of the
BOV star CD − 57 ◦ 3120 (see Discussion). North is up, east to the left.
10-Q very much!
Orin

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Ann » Thu Nov 10, 2022 5:15 am

orin stepanek wrote: Wed Nov 09, 2022 1:32 pm wr18_woronow_960.jpg
Interesting photo; can someone locate the star?
https://image.shutterstock.com/image-ph ... 814405.jpg Awesome looking kitty!
APOD 9 November 2022 detail annotated.png

Ann
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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by VictorBorun » Thu Nov 10, 2022 5:50 am

My eyes see a cylinder wall, centred at WR18 and seen at an angle, that is touching, from inside, an ellipsoid shell, centred at some 4'30'' to 8:30 o'clock from WR18
wr18 overlay 2 ell.jpg
wr18 ell.jpg
...
Click to view full size image 1 or image 2
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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by VictorBorun » Thu Nov 10, 2022 10:56 am

Or the larger ellipsoid may has yet another sphere, concentrically inscribed

wr18 overlay 2 ell 2.jpg
wr18 ell 2.jpg
...
Click to view full size image 1 or image 2
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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by orin stepanek » Thu Nov 10, 2022 1:50 pm

Ann wrote: Thu Nov 10, 2022 5:15 am
orin stepanek wrote: Wed Nov 09, 2022 1:32 pm wr18_woronow_960.jpg
Interesting photo; can someone locate the star?
https://image.shutterstock.com/image-ph ... 814405.jpg Awesome looking kitty!

APOD 9 November 2022 detail annotated.png


Ann
Thank you Ann; I figured it out from Victor's directions! Iguess I was looking for something larger in the photo! :oops:
Orin

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by minhlead » Fri Nov 11, 2022 5:00 am

Chris Peterson wrote: Wed Nov 09, 2022 2:04 pm
AstroLux wrote: Wed Nov 09, 2022 8:42 am Unfortunately this image has been overprocessed so much that the actual data has been destroyed and the final image looks really bad.
No, it has been heavily processed, with the intent of revealing specific structural detail, not to look "good". A completely normal and necessary process used by scientific imagers everywhere.
The guy used Topaz AI to process the image and the AI based software has a tendency of inventing details where there is none.
So there is as much scientific data in this picture as an oil painting.
https://www.astrobin.com/x0kpsk/
Some other work similiar to this
https://www.astrobin.com/q4xr2z/ (a lot of features invented out of thin air).
https://www.astrobin.com/r3eajq/ also nonexistent features being lift up from the noise

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Chris Peterson » Fri Nov 11, 2022 5:09 am

minhlead wrote: Fri Nov 11, 2022 5:00 am
Chris Peterson wrote: Wed Nov 09, 2022 2:04 pm
AstroLux wrote: Wed Nov 09, 2022 8:42 am Unfortunately this image has been overprocessed so much that the actual data has been destroyed and the final image looks really bad.
No, it has been heavily processed, with the intent of revealing specific structural detail, not to look "good". A completely normal and necessary process used by scientific imagers everywhere.
The guy used Topaz AI to process the image and the AI based software has a tendency of inventing details where there is none.
So there is as much scientific data in this picture as an oil painting.
https://www.astrobin.com/x0kpsk/
Some other work similiar to this
https://www.astrobin.com/q4xr2z/ (a lot of features invented out of thin air).
https://www.astrobin.com/r3eajq/ also nonexistent features being lift up from the noise
Maybe, maybe not.
Chris

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by minhlead » Fri Nov 11, 2022 5:23 am

Chris Peterson wrote: Fri Nov 11, 2022 5:09 am
minhlead wrote: Fri Nov 11, 2022 5:00 am
Chris Peterson wrote: Wed Nov 09, 2022 2:04 pm

No, it has been heavily processed, with the intent of revealing specific structural detail, not to look "good". A completely normal and necessary process used by scientific imagers everywhere.
The guy used Topaz AI to process the image and the AI based software has a tendency of inventing details where there is none.
So there is as much scientific data in this picture as an oil painting.
https://www.astrobin.com/x0kpsk/
Some other work similiar to this
https://www.astrobin.com/q4xr2z/ (a lot of features invented out of thin air).
https://www.astrobin.com/r3eajq/ also nonexistent features being lift up from the noise
Maybe, maybe not.
What do you mean by "maybe not"?
If by that you meant maybe he used Topaz maybe not then the author said specifically in the description that he used Topaz.
And a quick zoom in reveals at least several sharpen/detail inventing artifacts. https://photos.app.goo.gl/ne3ktqcjLxn7hANK8

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Chris Peterson » Fri Nov 11, 2022 1:32 pm

minhlead wrote: Fri Nov 11, 2022 5:23 am
Chris Peterson wrote: Fri Nov 11, 2022 5:09 am
minhlead wrote: Fri Nov 11, 2022 5:00 am
The guy used Topaz AI to process the image and the AI based software has a tendency of inventing details where there is none.
So there is as much scientific data in this picture as an oil painting.
https://www.astrobin.com/x0kpsk/
Some other work similiar to this
https://www.astrobin.com/q4xr2z/ (a lot of features invented out of thin air).
https://www.astrobin.com/r3eajq/ also nonexistent features being lift up from the noise
Maybe, maybe not.
What do you mean by "maybe not"?
If by that you meant maybe he used Topaz maybe not then the author said specifically in the description that he used Topaz.
And a quick zoom in reveals at least several sharpen/detail inventing artifacts. https://photos.app.goo.gl/ne3ktqcjLxn7hANK8
I mean that there are many image analysis techniques that create artifacts and nevertheless remain useful for showing structure. That doesn't qualify as "over processing".
Chris

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by minhlead » Sat Nov 12, 2022 5:40 pm

Chris Peterson wrote: Fri Nov 11, 2022 1:32 pm
minhlead wrote: Fri Nov 11, 2022 5:23 am
Chris Peterson wrote: Fri Nov 11, 2022 5:09 am

Maybe, maybe not.
What do you mean by "maybe not"?
If by that you meant maybe he used Topaz maybe not then the author said specifically in the description that he used Topaz.
And a quick zoom in reveals at least several sharpen/detail inventing artifacts. https://photos.app.goo.gl/ne3ktqcjLxn7hANK8
I mean that there are many image analysis techniques that create artifacts and nevertheless remain useful for showing structure. That doesn't qualify as "over processing".
The problem was how do you know what feature was "invented" by the software and what is not.
Pushing the histogram to bring out the detail is different from throwing data into a machine learning without knowing what kind of data set it was fed. That is why you do not use a general purposse machine learning engine for a scientific project.
APOD, as a scientific oriented org should never accepted such an image. I'd like to welcome thoughts from one of the apod editor so we'd know what did they think.

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Re: APOD: The Asymmetric Nebula Surrounding 18... (2022 Nov 09)

Post by Chris Peterson » Sat Nov 12, 2022 5:57 pm

minhlead wrote: Sat Nov 12, 2022 5:40 pm
Chris Peterson wrote: Fri Nov 11, 2022 1:32 pm
minhlead wrote: Fri Nov 11, 2022 5:23 am
What do you mean by "maybe not"?
If by that you meant maybe he used Topaz maybe not then the author said specifically in the description that he used Topaz.
And a quick zoom in reveals at least several sharpen/detail inventing artifacts. https://photos.app.goo.gl/ne3ktqcjLxn7hANK8
I mean that there are many image analysis techniques that create artifacts and nevertheless remain useful for showing structure. That doesn't qualify as "over processing".
The problem was how do you know what feature was "invented" by the software and what is not.
Pushing the histogram to bring out the detail is different from throwing data into a machine learning without knowing what kind of data set it was fed. That is why you do not use a general purposse machine learning engine for a scientific project.
APOD, as a scientific oriented org should never accepted such an image. I'd like to welcome thoughts from one of the apod editor so we'd know what did they think.
People use general purpose machine learning tools for scientific analysis all the time. There are all kinds of clues that structure is real, even if detail is not. Long linear or curved structures, for instance, are unlikely to be artifacts.
Chris

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