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Nucleosynthesis

Page history last edited by PBworks 14 years ago

Nucleosynthesis processes

 

Big Bang Nucleosynthesis

Occurred within the first three minutes of the universe.

Generated:

  • Hydrogen
  • Deuterium
  • Helium-3
  • Helium-4
  • Lithium-7

 

Stellar Nucleosynthesis

Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the heavier elements. The prime energy producer in the sun is the fusion of hydrogen to helium, which occurs at a minimum temperature of 3 million kelvins.

Largely responsible for isotopes of:

Hydrogen Burning Process

  • Helium
  • Carbon
  • Nitrogen
  • Oxygen
  • Fluorine

 

Helium Burning Process

  • Beryllium
  • Oxygen
  • Neon
  • Magnesium

 

Carbon Burning

  • Hydrogen
  • Helium
  • Magnesium
  • Sodium
  • Neon
  • Oxygen

 

Neon Burning

  • Oxygen
  • Helium
  • Magnesium

 

Oxygen Burning

  • Sulphur
  • Phosphorus
  • Silicon
  • Magnesium

 

Silicon Burning

  • Sulphur
  • Argon
  • Calcium
  • Titanium
  • Chromium
  • Iron
  • Nickel

 

Nucleosynthesis of heavier elements

Neutron Capture

R process:

Rf - Ds

 

S Process:

Sr, Y - Bi, Po, Pb

 

Proton Capture

P process:

  • Pt
  • Yb

 

Supernova Nucleosynthesis

Supernova nucleosynthesis refers to the production of new chemical elements inside supernovae. Supernovae often occur when a massive star, usually a red giant, reaches iron in its nuclear fusion (or burning) processes. Due to the large amounts of energy released in a supernova explosion much higher temperatures are reached than stellar temperatures. Higher temperatures allow for an environment where elements up to the atomic mass of 254 are formed, californium being the heaviest known of, though it is seen only as a synthetic element on Earth.

 

Most of the elements heavier than oxygen that make life possible were created in supernovas.

 

Cosmic Ray Spallation

Cosmic ray spallation is a form of naturally occurring nuclear fission and nucleosynthesis. It refers to the formation of elements from the impact of cosmic rays on an object. Cosmic rays are energetic particles outside of Earth ranging from a stray electron to gamma rays. These cause spallation when a fast moving particle, usually a proton, part of a cosmic ray impacts matter, including other cosmic rays. The result of the collision is the expulsion of large members of nucleons (protons and neutrons) from the object hit. This process goes on not only in deep space, but in our upper atmosphere due to the impact of cosmic rays. This process also largely results from the impact of cosmic rays against the interstellar medium.

 

Largely responsible for isotopes of:

  • Lithium
  • Beryllium
  • Boron
  • Carbon (14)
  • Aluminium
  • Chlorine
  • Iodine
  • Neon

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