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Questions tagged [nucleosynthesis]

Questions to do with how new atomic nuclei are created inside the universe.

12 questions with no upvoted or accepted answers
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Neutron star r-process nucleosynthesis

The $r$-process in supernovae happens when a high flux of neutrons irradiates the heaviest abundant nuclei (in the region of iron), resulting in endothermic nuclear reactions. To the extent that at ...
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54 views

Elements of celestial bodies

Could someone tell me if it proceeds as well as which or which works would allow us to conclude the origin of the elements for different types of bodies or celestial phenomena? Edited: This image was ...
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35 views

Expanded element (and molecule) abundance graph?

There is the "classical" nucleosynthesis timeline chart where the $\log ({\rm mass \,fraction})$ is plotted as a function of $\log(t)$ where $t$ is in seconds after the big bang, looking e.g....
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48 views

How do we know or predict which particles were present before Big Bang Nucleosynthesis occurred?

I'm reading Carroll and Ostlie's "An Introduction to Modern Astrophysics". In the BBN section, they describe that the universe contains a mixture of photons, electron-positron pairs, and ...
2
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39 views

Mass required for a certain fusion process

Suppose we have a density model $$ρ = ρ_c (1-r/R)$$ where $ρ$ is density, ${}_c$ means central, and $R$ is the stellar radius. Let's call the temperature for that fusion process to begin, $T_f$. I ...
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54 views

How scientists estimated the number of near-Earth supernovae over the last 11 million years?

According to this article on wikipedia, An estimated 20 supernova explosions have happened within 300 pc of the Earth over ...
2
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50 views

How the observed deuterium abundance constrains big bang nucleosynthesis?

I know deuterium can be used as a good tracer to constrain the big bang nucleosynthesis. But can anyone tell me the in details how this is actually done?
2
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56 views

pp-Chain reactions involving $^{3}_{2}He$ - differences in S-factor

So I was looking at the pp-chain reactions that take place inside stars in a bit more detail. I got confused about the massive differences in reaction efficiencies concerning two reactions $^{3}_{2}He$...
1
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40 views

Photodisintegration vs Spallation

Is photodisintegration belongs to a form of spallation? Is photodisintegration only limited to nucleus hit by high energy gamma-ray, whereas the nucleus in spallation can be hit by any ​high energy ...
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69 views

Can someone tell me the contribution of s-, r-, and p-isotope processes to copper?

I have looked for relevant information in the paper Chemical evolution with rotating massive star yields II. A new assessment of the solar s- and r- process components before, but unfortunately, it ...
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25 views

Relation between core mass and red giant mass?

Yes, the title might be confusing (I'd appreciate some more clarification on it :D ). I have an estimated mass of hydrogen in the core of a star, and how much hydrogen will be in the core when the ...
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23 views

How did the amount of nuclide produced by s- and r-process changed over time?

For a exercise I need to find out how the amount of nuclide produced by s- and r-process changed over time and I also need to draw a schematic diagram of the s-/r-ratio vs. time from 13.6 Ga till ...