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Questions tagged [nucleosynthesis]

Nucleosynthesis is the process by which stars create heavier elements from hydrogen and helium

Nucleosynthesis is the process by which stars create heavier elements from hydrogen and helium. This includes the process of fusion which can synthesize up to iron, and if the star has sufficient mass, elements beyond iron through stellar collapse and subsequent nova and supernova explosion.

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Why is there a scarcity of lithium?

One of the major impediments to the widespread adoption of electric cars is a shortage of lithium for the batteries. I read an article a while back that says that there is simply not enough lithium available on the entire planet to make enough…
Mason Wheeler
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Why is hydrogen the most abundant element in the Universe?

Hydrogen is the most abundant element in nature. Does cosmological nucleosynthesis provide an explanation for why is this the case? Is the explanation quantitatively precise?
Solidification
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Does all hydrogen originate from the Big Bang?

I was wondering, if every single hydrogen in the universe originate from the time about ~3 min after the Big Bang. I know there are nuclear fusion processes going on in stars like the pp-chain reaction which 'emit' hydrogen, too, but those reactions…
rtime
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Why is nitrogen (with 7 protons and 7 neutrons) so much more abundant than any other odd-odd isotope?

Having an even number of neutrons and/or an even number of protons tends to make a nucleus more stable against radioactive decay. There are only 5 stable nuclei with both an odd number of neutrons and an odd number of protons: hydrogen-2…
John C. Baez
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Why do main sequence stars get bigger and more luminous as they age?

As stars age, the concentration of hydrogen in the core decreases, which lowers the power output, causing an imbalance between outward radiation pressure and inward gravitational pressure. This causes the core to collapse so that it becomes denser…
never took courses but why
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How do scientists know Iron-60 is created during supernovae?

I know that the meteoroids contain Ni-60, which is formed after decaying Fe-60, and as per my study, I got to know that Fe-60 is formed during the time of a supernova. But I wonder how scientists know/find that these elements were created during…
Dhiraj Dhakal
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Why is more Fe-56 than Ni-62 produced by fusion in massive stars?

Suppose we create an Fe-56 nucleus and an Ni-62 nucleus, each from individual protons and neutrons. In the case of Ni-62, more mass per nucleon is converted to binding energy. Thus we could argue the Ni-62 nucleus to be more strongly bound than the…
gamma1954
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What would be the first compound formed in the early universe?

This may sound like a chemistry problem, but I suspect this would have lot to do with primordial nucleosynthesis. After all physics underlies everything. It is believed that several elements were formed during this period. Wikipedia…
sampathsris
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Why does stellar nucleosynthesis not turn lithium into boron

Another discussion on this site (Why is there a scarcity of lithium?) as well as the wikipedia page on Lithium burning (https://en.wikipedia.org/wiki/Lithium_burning), have helped me understand why stellar nucleosynthesis doesn't generally produce a…
Scott Forschler
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Why did the Big Bang produce hydrogen?

I know that first generation stars' main fuel was Hydrogen. I know the Big Bang happened at some point in time. Now if the strong force exists, then why aren't different, higher mass, number elements produced? why was there single proton nucleus…
baponkar
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If there are long-lived elements in the Island of stability, why are they not present in Nature?

To my understanding, some (but not many) physicists speculate that the Island of stability may contain long-lived elements, as in a billion or so years. But couldn't we rule that out just by the nonexistence of such elements in Nature?
nordmarj
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Why is the deuterium bottleneck temperature 0.1 MeV?

During big bang nucleosynthesis (BBN), deuterium has a lower binding energy per nucleon (~1.1 MeV) than the other similar nuclei, and so prevents heavy elements from forming until the temperature drops below about 0.1 MeV. Above 0.1 MeV, deuterium…
arow257
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Big Bang Nucleosynthesis

In the very early universe, the hot plasma consisted of fixed amount of radiation (photons and neutrinos) and matter (electrons, protons, neutrons, etc). There were many competing reaction taking place and using statistical methods I understand…
user32023
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Why is lithium burned at lower temperatures than hydrogen inside stars?

The destruction of lithium inside stars through the reaction $$ ^{7}_{3}{\rm Li} + {\rm p} \rightarrow 2\ ^{4}_{2}{\rm He}$$ takes place at just $\sim 3\times 10^6$ K. This is much lower than the temperatures ($\sim 10^7$ K) required to turn…
ProfRob
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${^{180}}\mathrm{Ta}^\mathrm{m}$ and absent stable species

Writing a piece for laymen which happens to mention nucleosynthesis, I realise that I do not know the answer to the following question: Are there stable isotopes which do not occur in nature? One could make an equally striking point either…
Martin Kochanski
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