Is This Picture Really About the CNO Cycle?

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    Cno cycle Cycle
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Discussion Overview

The discussion revolves around the accuracy of a picture purportedly depicting the CNO cycle in stellar nucleosynthesis. Participants explore whether the image correctly represents the CNO cycle or if it pertains to other processes such as the alpha process or the triple alpha process.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that the CNO cycle involves nitrogen rather than neon, suggesting a misunderstanding in the image's representation.
  • One participant proposes that the image might be referring to the alpha process, which involves carbon and helium, rather than the CNO cycle.
  • Another participant mentions that the CNO cycle produces helium rather than consuming it, indicating a potential misrepresentation in the image.
  • There is a suggestion that the picture could be illustrating the triple alpha process, followed by carbon and neon burning processes, rather than the CNO cycle itself.

Areas of Agreement / Disagreement

Participants express differing views on whether the image accurately represents the CNO cycle, with some agreeing that it does not, while others propose alternative interpretations involving different nuclear processes. The discussion remains unresolved regarding the correct identification of the processes depicted in the image.

Contextual Notes

Participants reference various nuclear processes and their relationships, but there is uncertainty regarding the specific processes illustrated in the picture. The discussion highlights the complexity of stellar nucleosynthesis and the potential for confusion between different cycles and processes.

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
 
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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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