nucleosynthesis
nucleosynthesis The process by which elements are formed. Modern theories suggest that nucleosynthesis is intimately linked with the stages in the life-cycle of stars (stellar evolution), and that, commencing with hydrogen, heavier elements are created by nuclear fusion of lighter nuclides at the temperatures and pressures existing in the cores of stars. Because the lighter elements are consumed to produce energy these thermonuclear reactions are referred to as ‘burning’, although they have nothing to do with combustion. The stages of stellar evolution conform well with the overall pattern of peaks and troughs in the cosmic abundance of elements in order of increasing atomic number (Z). During the first and longest (main-sequence) phase, hydrogen (which is by far the most abundant element of the stellar material) is consumed to produce helium (hydrogen burning). Hydrogen burning is followed in turn by helium burning, carbon and oxygen burning, and silicon burning, each phase producing heavier elements from lighter ones. The heaviest elements are formed in the last stages in the sequence: the equilibrium (e) process (coinciding with the ‘iron peak’ elements, Cr, Mn, Fe, Co, and Ni), followed by the ‘slow neutron (s) process producing elements up to Bi (atomic number 83), and finally (in supernova events) the rapid neutron (r) process producing elements with atomic number greater than 83. See also PROTOSTAR.
More From encyclopedia.com
Calvin Cycle , Calvin cycle (photosynthetic carbon reduction cycle) The metabolic pathway of the light-independent stage of photosynthesis, which occurs in the stro… Nuclear Fusion , Nuclear fusion is the process by which two light atomic nuclei combine to form one heavier atomic nucleus. As an example, a proton (the nucleus of a… Urea cycle , urea cycle (ornithine cycle) The series of biochemical reactions that converts ammonia, which is highly toxic, and carbon dioxide to the much less to… Fusion , Fusion
Nuclear fusion is the process by which two light atomic nuclei combine to form one heavier atomic nucleus. As an example, a proton (the nucleu… Cycle , Skip to main content
cycle
cycle •cackle, crackle, grackle, hackle, jackal, mackle, shackle, tackle •ankle, rankle •Gaskell, mascle, paschal •taberna… Obliquity Of The Ecliptic , obliquity of the ecliptic See MILANKOVICH CYCLES.
About this article
nucleosynthesis
All Sources -
You Might Also Like
NEARBY TERMS
nucleosynthesis