Where do neutrons in the sun come from?

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Discussion Overview

The discussion centers around the origin of neutrons in the Sun, exploring the processes involved in stellar nucleosynthesis, particularly in the context of hydrogen and helium production. Participants also touch on related topics such as deuterium and neutrinos, indicating a mix of theoretical and conceptual inquiries.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that neutrons in the Sun are produced during the conversion of hydrogen to helium through processes like the proton-proton chain.
  • There is mention of helium being produced during the Big Bang, suggesting that not all stars start solely from hydrogen.
  • Questions arise about the nature of neutrinos, with some participants seeking further information on subatomic particles.
  • One participant explains that deuterium is an isotope of hydrogen, produced through specific reactions involving protons, positrons, and neutrinos.
  • Another participant discusses the rarity of deuterium-producing events in the Sun and the common occurrence of diprotons, which decay back into protons.
  • There are references to industrial and scientific methods for producing deuterium, including processes involving heavy water.
  • Some participants mention neutron drip and inverse beta decay as potential processes, contingent on density conditions typically found in compact stars.

Areas of Agreement / Disagreement

The discussion contains multiple competing views and remains unresolved regarding the specific processes and conditions under which neutrons are produced in the Sun.

Contextual Notes

Participants express uncertainty about the density conditions required for certain processes like neutron drip, indicating a dependence on specific astrophysical contexts.

Quantum Velocity
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If star start from a big ball of hidrogen and the all the neutron to make helium.
Thx for help!
 
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That's a fair question.

First, there was some Helium produced in the big bang, so not 100% of the first stars was Hydrrogen. But I think the real answer to your question is this:

678px-FusionintheSun.svg.png


https://en.wikipedia.org/wiki/Nuclear_fusion#Nuclear_fusion_in_stars said:
The proton-proton chain dominates in stars the size of the Sun or smaller.
 
what is neutrion
 
by the way thanks for helping me understand
 
Quantum Velocity said:
what is neutrion

A neutrino is a very strange particle with just a tiny bit of mass.

See https://en.wikipedia.org/wiki/Neutrino

There are very many kinds of subatomic particles. Do you want to learn more about them in general? If yes, I'm sure that other PF members can recommend a tutorial or a starting textbook.
 
anorlunda said:
Do you want to learn more about them in general
Yes pls
 
Someone please help this person with a recommended tutorial, textbook or someplace for him to learn.
 
In the Sun, deuterium-producing events are rare. Diprotons are the much more common result of proton-proton reactions within the star, and diprotons almost immediately decay back into two protons. Since the conversion of hydrogen to helium is slow, the complete conversion of the hydrogen in the core of Earth's Sun is calculated to take more than 1010 (ten billion) years.
 
What is deuterium-producing
 
  • #10
Quantum Velocity said:
What is deuterium-producing
Deuterium is the isotope of hydrogen with one neutron and one proton. It can be produced by the reaction at the top in the diagram anorlunda posted above: two protons combine, emitting a positron and and a neutrino and turning into deuterium.
 
  • #11
Quantum Velocity said:
What is deuterium-producing

Deuterium is produced for industrial, scientific and military purposes, by starting with ordinary water—a small fraction of which is naturally-occurring heavy water—and then separating out the heavy water by the Girdler sulfide process, distillation, or other methods.

In theory, deuterium for heavy water could be created in a nuclear reactor, but separation from ordinary water is the cheapest bulk production process :woot:

The world's leading supplier of deuterium was Atomic Energy of Canada Limited, in Canada, until 1997, when the last heavy water plant was shut down. Canada uses heavy water as a neutron moderator for the operation of the CANDU reactor design.
 
Last edited:
  • #12
Neutron drip and inverse beta decay are possibilities.
But it depends of its density, nêutron drip occours above a level of density that i believe only happen in compact stars
 

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