Is This Picture Really About the CNO Cycle?

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SUMMARY

The discussion clarifies that the image in question does not accurately represent the CNO cycle, which primarily involves the conversion of hydrogen into helium through a series of reactions involving carbon, nitrogen, and oxygen. Participants confirm that the CNO cycle produces helium rather than consuming it, and they suggest that the image may instead depict the triple-alpha process or the carbon and neon burning processes. Key reactions include Carbon (C) transforming into Nitrogen (N) and then Oxygen (O), with the full cycle detailed on the CNO cycle Wikipedia page.

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Stephanus
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Dear PF Forum,
StellarNucleoSynthesis1.JPG

Is this picture correct?
Or it is not CNO Cycle?
I get that video from this
Thanks for any answer
 
Last edited:
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The CNO cycle involves nitrogen rather than neon.
 
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Vagn said:
The CNO cycle involves nitrogen rather than neon.
Yep, I think it makes more sense.

Carbon -> Nitrogen -> Oxygen
12 -> 14 -> 16
But I've seen it twice if not three times on youtube on diferent videos.
So perhaps what they actually mean is alpha process?
Carbon + He4 -> Oxygen
Oxygen + He4 -> Neon?

Thanks

Steven
 
Stephanus said:
Yep, I think it makes more sense.

Carbon -> Nitrogen -> Oxygen
12 -> 14 -> 16
But I've seen it twice if not three times on youtube on diferent videos.
So perhaps what they actually mean is alpha process?
Carbon + He4 -> Oxygen
Oxygen + He4 -> Neon?

Thanks

Steven
The CNO cycle produces 4He, not consumes it. There are intermediate stages involving neon in some variations of the CNO cycles, but these only occur at very high temperatures. The basic cycle is carbon>nitrogen>oxygen>carbon, the full reaction is given on the CNO cycle wiki page.
 
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Stephanus said:
Is this picture correct?
Or it is not CNO Cycle?

That picture is not the CNO cycle, which, as Vagn pointed out, converts hydrogen to helium in a multi-step process.

Stephanus said:
So perhaps what they actually mean is alpha process?
Carbon + He4 -> Oxygen
Oxygen + He4 -> Neon?

Actually I think the picture is referring to the triple alpha process, then the carbon burning process, and then the neon burning process.

http://en.wikipedia.org/wiki/Triple-alpha_process
http://en.wikipedia.org/wiki/Carbon-burning_process
http://en.wikipedia.org/wiki/Neon-burning_process
 
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