High School Can iron form via processes like the r- or s-process?

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SUMMARY

Iron formation in stars primarily occurs through silicon burning and the beta-decay of neutron-rich isotopes, particularly around the iron peak. The discussion highlights that while silicon burning produces the majority of iron, processes like the r-process and alpha process also contribute to the formation of isotopes such as Fe-57 and Fe-58. Additionally, the stability of isotopes like Mn-56 and Cr-52 is noted, with implications for the s-process and energy release during neutron capture. The formation of Fe-54 is also explored, suggesting potential pathways through the alpha process and photodisintegration.

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  • Understanding of stellar nucleosynthesis processes, specifically silicon burning and the r-process.
  • Knowledge of beta-decay and its role in isotope formation.
  • Familiarity with isotopes of iron and their natural abundance, including Fe-56, Fe-57, and Fe-58.
  • Concepts of neutron capture processes, including the s-process and alpha process.
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  • Research the mechanisms of stellar nucleosynthesis, focusing on silicon burning and its products.
  • Study the r-process and its role in forming heavy isotopes, particularly in supernova events.
  • Explore the alpha process and its implications for the formation of isotopes like Fe-54.
  • Investigate the effects of photodisintegration in stellar environments and its contribution to nucleosynthesis.
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TL;DR
Can iron form via processes other than during silicon burning? e.g. the r- or s-process
Hi,

I was wondering by what other methods iron can form in stars? Iron can form during silicon burning and i assume it can also form via the beta- decay of neutron rich isotopes around the iron peak? Are these athe only two processes that relate to the cosmogenesis of iron?
 
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I'm certain there will be the occasional iron atom formed in these processes - but silicon burning produces so much more that it doesn't matter.
It might contribute to Fe-58 (0.3% of natural iron) and Fe-57 (2.1%).

Edit: Mn-56 has a half life of only 2.5 hours, so the s-process won't lead to Fe-57 and Fe-58.
 
mfb said:
...Edit: Mn-56 has a half life of only 2.5 hours, so the s-process won't lead to Fe-57 and Fe-58.
Chrome 52 is stable. adding neutrons to cr 53, and then cr54 are still stable. One more gets Cr55 which then beta decays to Mn55 which is stable. One more neutron is Mn 56 which beta decays to Fe56. Then add neutrons to get Fe 57 and Fe 58.

Vanadium 51 is stable. add neutron for V52 which beta decays to Cr52. All isotopes of Ti are stable 46 to 50. and Ti51 decays to V51. Sc46 beta decays to Ti46. Ca 45 decays to Sc 45. You can keep working backwards all the way.
 
Is it still the s-process if you start with Fe-56 that has so much more important origins? Eh, whatever.
Surprisingly, Fe56+n -> Fe-57 releases energy.
 
Whereas s-process skips Fe-54. How is Fe-54 formed?
Since Fe-59 has half-life 45 days, r-process forms Fe-60... which, however, has half-life 2,6 million years.
 
snorkack said:
Whereas s-process skips Fe-54. How is Fe-54 formed?
Since Fe-59 has half-life 45 days, r-process forms Fe-60... which, however, has half-life 2,6 million years.

Alpha process maybe. Ti-46 becomes Cr-50 becomes Fe-54. Photodisintegration of Nickel 58 might get the job done too. Pair instability supernova would have hydrogen present while temperatures are high enough to shove protons in there. So decay of Co-54.

I do not know what happens if you start the alpha process from Oxygen-18 instead of Oxygen-16.
 
https://en.wikipedia.org/wiki/MoM-z14 Any photon with energy above 24.6 eV is going to ionize any atom. K, L X-rays would certainly ionize atoms. https://www.scientificamerican.com/article/whats-the-most-distant-galaxy/ The James Webb Space Telescope has found the most distant galaxy ever seen, at the dawn of the cosmos. Again. https://www.skyatnightmagazine.com/news/webb-mom-z14 A Cosmic Miracle: A Remarkably Luminous Galaxy at zspec = 14.44 Confirmed with JWST...

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