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In astrophysics, stellar nucleosynthesis is the creation of chemical elements by nuclear fusion reactions within stars. Stellar nucleosynthesis has occurred since the original creation of hydrogen, helium and lithium during the Big Bang. As a predictive theory, it yields accurate estimates of the observed abundances of the elements.
The first direct proof that nucleosynthesis occurs in stars was the astronomical observation that interstellar gas has become enriched with heavy elements as time passed. As a result, stars that were born from it late in the galaxy, formed with much higher initial heavy element abundances than those that had formed earlier.
Supernova nucleosynthesis is the nucleosynthesis of chemical elements in supernova explosions.. In sufficiently massive stars, the nucleosynthesis by fusion of lighter elements into heavier ones occurs during sequential hydrostatic burning processes called helium burning, carbon burning, oxygen burning, and silicon burning, in which the byproducts of one nuclear fuel become, after ...
The slow neutron-capture process, or s-process, is a series of reactions in nuclear astrophysics that occur in stars, particularly asymptotic giant branch stars.The s-process is responsible for the creation (nucleosynthesis) of approximately half the atomic nuclei heavier than iron.
Observations indicate a strong negative correlation between a star's initial heavy element content (known as the metallicity) and its age. More recently formed stars tend to have higher metallicity. The early Universe consisted of only the light elements formed during Big Bang nucleosynthesis.
Based on known resonances, by 1952 it seemed impossible for ordinary stars to produce carbon as well as any heavier element. [14] Nuclear physicist William Alfred Fowler had noted the beryllium-8 resonance, and Edwin Salpeter had calculated the reaction rate for 8 Be, 12 C, and 16 O nucleosynthesis taking this resonance into account.
In stars, rapid nucleosynthesis proceeds by adding helium nuclei (alpha particles) to heavier nuclei. As mentioned above, this process ends around atomic mass 56. [11] Decay of nickel-56 explains the large amount of iron-56 seen in metallic meteorites and the cores of rocky planets.
A version of the periodic table indicating the origins – including big bang nucleosynthesis – of the elements. All elements above 103 are also man-made and are not included. Big Bang nucleosynthesis produced very few nuclei of elements heavier than lithium due to a bottleneck: the absence of a stable nucleus with 8 or 5 nucleons. This ...