APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

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APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by APOD Robot » Mon Jun 27, 2022 4:05 am

Image The Gum Nebula over Snowy Mountains

Explanation: The Gum Nebula is so large and close it is actually hard to see. This interstellar expanse of glowing hydrogen gas frequently evades notice because it spans 35 degrees -- over 70 full Moons -- while much of it is quite dim. This featured spectacular 90-degree wide mosaic, however, was designed to be both wide and deep enough to bring up the Gum -- visible in red on the right. The image was acquired late last year with both the foreground -- including Haba Snow Mountain -- and the background -- including the Milky Way's central band -- captured by the same camera and from the same location in Shangri-La, Yunnan, China. The Gum Nebula is so close that we are only about 450 light-years from the front edge, while about 1,500 light-years from the back edge. Named for a cosmic cloud hunter, Australian astronomer Colin Stanley Gum (1924-1960), the origin of this complex nebula is still being debated. A leading theory for the origin of the Gum Nebula is that it is the remnant of a million year-old supernova explosion, while a competing theory holds that the Gum is a molecular cloud shaped over eons by multiple supernovas and the outflowing winds of several massive stars.

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VictorBorun
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by VictorBorun » Mon Jun 27, 2022 5:19 am

I wonder how this nebula ended up so unspheric.
Was it the galaxy disk differential rotation?
Gum Nebula..jpg
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by Ann » Mon Jun 27, 2022 5:25 am

APOD 27 June 2022 Gum Nebula annotated stars.png

The APOD looks fantastic, as if the sky was on soft reddish fire.

There are a number of great stars here, too.


Tau CMa is the luminary of beautiful cluster NGC 2362. Another O-type star, 29 CMa, is located close to it.

Delta CMA is a yellow-white supergiant, a huge star whose "surface temperature" is very similar to the temperature of the Sun. If this star was placed at the center of the solar system, it would swallow the Earth.

Eta CMa is a blue supergiant.

Epsilon CMA, Adhara, is the greatest source of ultraviolet light in the nearby universe. Adhara is a bright giant of spectral class B2II, and it is "only" some 400 light-years away, quite comparable to the Pleiades.

Sigma CMa is a bright red giant or a lesser red supergiant, and Pi Puppis is a lesser red supergiant.


NGC 2451 contains a bright red giant, HD 63032.

Zeta Puppis is a brilliant O-type star of spectral type O5Iaf. It radiates some 12,000 solar luminosities at optical wavelengths, but because it is such a hot O-type stars whose blackbody curve peaks far into the ultraviolet part of the spectrum, its total energy production is over 500,000 suns.

Gamma Velorum is an even more remarkable star than Zeta Puppis. It is a quadruple star whose main components are one O-type giant and one Wolf Rayet star. The Wolf Rayet component is going to explode as a Type Ib supernova.

It has been speculated that Zeta Puppis and Gamma Velorum could provide enough ultraviolet light to ionize the Gum Nebula. But today, a supernova remnant is considered an equally likely source of the nebula.

Interestingly, Zeta Puppis is a runaway star. It is also a single star, which is most unusual for very massive stars. It is quite possible that Zeta Puppis once had a companion that exploded as a supernova and sent Zeta Puppis flying.

Ann
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Ann
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by Ann » Mon Jun 27, 2022 6:00 am

VictorBorun wrote: Mon Jun 27, 2022 5:19 am I wonder how this nebula ended up so unspheric.
Was it the galaxy disk differential rotation?
Gum Nebula..jpg
It's not so unspheric:


In the annotated picture above, ζ Pup is Zeta Puppis (or Zeta Pup) and γ Vel is Gamma Velorum. It is interesting to see that there is a hole in the Gum Nebula between Zeta Puppis and Gamma Velorum, as if something blew there.

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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by VictorBorun » Mon Jun 27, 2022 7:51 am

Ann wrote: Mon Jun 27, 2022 6:00 am It's not so unspheric:
In the annotated picture above, ζ Pup is Zeta Puppis (or Zeta Pup) and γ Vel is Gamma Velorum. It is interesting to see that there is a hole in the Gum Nebula between Zeta Puppis and Gamma Velorum, as if something blew there.

Ann
If the Gum Nebula is shaped like a tube then it's even less spherical:
Gum Nebula +2.jpg
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by VictorBorun » Mon Jun 27, 2022 10:15 am

I can remember a way to create a long tube with our line of sight as the axis: use a light echo to illuminate an ellipsoid with foci at Sun and the flasher.

The flasher has to be powerful in UV to excite the alpha hydrogen fluorescence.
The flasher has to be located at the dark center of the Gum Nebula a little further than 1400 ly.
The flash has to have happened a short while ago compared to 1400 years.

For example, let's put the flasher at the same 450 ly behind the hydrogen wall (containing the Gum light echo nebula) as Sun is in front of that wall.
Then by drawing accurately we obtain the time of the flash: 157 years ago
Update: sorry, 28 years ago.I made a drawing mistake. Here I update the scheme:
Gum Nebula +3.jpg
Now I understand Gum discovered the Gum Nebula before that. So this drawing contradicts the history :(
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Last edited by VictorBorun on Tue Jun 28, 2022 2:11 am, edited 2 times in total.

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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by orin stepanek » Mon Jun 27, 2022 11:45 am

GumMountain_WangJin_1080.jpg
Gum is Very big
.jpg
:mrgreen:
GumExpanseGleason1024.jpg
Lady almost looks like real photo!
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by De58te » Mon Jun 27, 2022 3:04 pm

APOD Robot wrote: Mon Jun 27, 2022 4:05 am A leading theory for the origin of the Gum Nebula is that it is the remnant of a million year-old supernova explosion, while a competing theory holds that the Gum is a molecular cloud shaped over eons by multiple supernovas and the outflowings of several massive stars.
What is the current status of this hotly contested origin debate? Million year-old supernova, or, multiple supernovas? So far the debate has reached an impasse. Neither side can be swayed. Both sides are determined to hold the fort and "stick to their gums!"

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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by Chris Peterson » Mon Jun 27, 2022 6:51 pm

orin stepanek wrote: Mon Jun 27, 2022 11:45 am Lady almost looks like real photo!
All I see is an X-ray of the Flying Spaghetti Monster.
Chris

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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by johnnydeep » Mon Jun 27, 2022 7:38 pm

Chris Peterson wrote: Mon Jun 27, 2022 6:51 pm
orin stepanek wrote: Mon Jun 27, 2022 11:45 am Lady almost looks like real photo!
All I see is an X-ray of the Flying Spaghetti Monster.
The FSM was what I first saw. I can't see any "Lady" let alone a pretty one, at all!
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by orin stepanek » Tue Jun 28, 2022 3:55 pm

file.jpg
.jpg
Oh well; to each his own1 I see a lady in the nebula! :wink:
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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by johnnydeep » Tue Jun 28, 2022 4:59 pm

orin stepanek wrote: Tue Jun 28, 2022 3:55 pm file.jpg.jpg
Oh well; to each his own1 I see a lady in the nebula! :wink:
Nope. Looks more like the face portion of an x-ray of the skull of an ectomorph to me:

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Re: APOD: The Gum Nebula over Snowy Mountains (2022 Jun 27)

Post by orin stepanek » Tue Jun 28, 2022 8:54 pm

johnnydeep wrote: Tue Jun 28, 2022 4:59 pm
orin stepanek wrote: Tue Jun 28, 2022 3:55 pm file.jpg.jpg
Oh well; to each his own1 I see a lady in the nebula! :wink:
Nope. Looks more like the face portion of an x-ray of the skull of an ectomorph to me:

ugh! You see bad things! :ohno:
Orin

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