Why is H burning not a B+ decay

In summary, the CNO cycle is a cycle that is used to produce elements with more protons in their nucleus. H burning is not considered to be B+ decay because it happens at a low temperature and does not happen at high temperatures like in exploding novae.
  • #1
The forgetful one
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TL;DR Summary
Hydrogen Burning in CNO cycle
Hello physics gurus out there.
Can someone please point me in the correct direction.
I am looking for reasons why Hydrogen burning is NOT considered to be B+ decay in the standard CNO cycle?

Thanks
The forgetful one
 
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  • #2
The forgetful one said:
Hydrogen burning is NOT considered to be B+ decay
Says who ?
 
  • #4
There are two beta+ decays as part of the CNO cycles.
 
  • #5
Apologies folks, I am just trying to learn this stuff.
The question I have is. If you consider the normal CNO cycle, why is H burning using this route not considered to be B+ decay limited.
 
  • #6
Limited is rather a key word in your question :smile: .
I take it you googled the CNO link ? It says
wiki said:
The limiting (slowest) reaction in the CNO-I cycle is the proton capture on ##\mathstrut ^{14}_{\ 7}\!N ##
 
  • #7
This is a totally new area for me, I am doing it to try and stop my grey matter from going all mushy.
I think I should just let it go and do flower arranging instead. :-)
 
  • #8
Just so you know: it's totally new for me too :oldeyes: ( but my background may be different)

However, I do like new areas of skills and knowledge. Not so sure about flower arranging, though ...
 
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  • #9
It is not limited at low temperature, like star cores.
The reason is that positron decay is one particle process that happens at a speed independent on temperature or density, and in case of the CNO cycle nuclei (N-13 and O-15) in a few minutes. Whereas at those low temperatures the proton captures happen once in millions of years.
At high temperatures, like in exploding novae where accumulated protium explodes, CNO cycle is sped up until the proton capture can happen in minutes, and then positron decay does become a limiting step. This allows the branches of hot CNO cycle, like N-13 captures a second proton before decay and goes through O-14.
 
  • #10
Terminology issue. B+ is an unusual term for beta decay.
 

FAQ: Why is H burning not a B+ decay

1. Why is H burning not a B+ decay?

H burning is not a B+ decay because they are two different processes that occur in different situations. H burning, also known as nuclear fusion, is a process that occurs in stars where hydrogen atoms combine to form helium. On the other hand, B+ decay is a type of radioactive decay that occurs in unstable atoms, where a proton is converted into a neutron and a positron is emitted.

2. Can hydrogen undergo B+ decay?

No, hydrogen cannot undergo B+ decay because it does not have enough protons to convert into neutrons. B+ decay can only occur in atoms with more than one proton, such as carbon or oxygen.

3. Why is H burning considered a more efficient energy source than B+ decay?

H burning is considered a more efficient energy source because it releases a larger amount of energy compared to B+ decay. In H burning, four hydrogen atoms combine to form one helium atom, releasing a large amount of energy in the process. B+ decay, on the other hand, only releases a small amount of energy when a proton is converted into a neutron.

4. Is H burning or B+ decay more common in the universe?

H burning is more common in the universe because it is the main process that powers stars. Almost all of the energy emitted by stars, including our sun, is a result of H burning. B+ decay, on the other hand, is a rare process that only occurs in unstable atoms.

5. How does H burning contribute to the creation of heavier elements?

H burning is responsible for the creation of heavier elements through a process called nucleosynthesis. As hydrogen atoms fuse together to form helium, this releases a large amount of energy which allows for the fusion of more and more atoms. This process continues until heavier elements, such as carbon, oxygen, and iron, are formed.

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