nucleosynthesis


nucleosynthesis
nucleosynthetic /nooh'klee oh sin thet"ik, nyooh'-/, adj.
/nooh'klee oh sin"theuh sis, nyooh'-/, n. Physics, Astron.
the formation of new atomic nuclei by nuclear reactions, thought to occur in the interiors of stars and in the early stages of development of the universe.
[1955-60; NUCLEO- + SYNTHESIS]

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Production on a cosmic scale of all the chemical elements from one or perhaps two simple types of atomic nuclei (see nucleus), those of hydrogen and helium.

Elements differ in the number of protons and isotopes of each element by the number of neutrons in their nuclei. One type of nucleus can be transformed into another by adding or removing protons, neutrons, or both, processes that go on in stars. Many of the first 26 elements (up to iron) and their present cosmic abundances can be accounted for by successive nuclear fusion reactions, beginning with hydrogen, in stellar cores. Heavier elements are believed to be created in the death of stars during supernova explosions, by capture of successive neutrons by lighter nuclei and decay of some of these neutrons into protons (with ejection of an electron and a neutrino each time).

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▪ chemical process
      production on a cosmic scale of all the species of chemical elements (chemical element) from perhaps one or two simple types of atomic nuclei, a process that entails large-scale nuclear reactions including those in progress in the Sun and other stars. Chemical elements differ from one another on the basis of the number of protons (fundamental particles that bear a positive charge) in the atomic nuclei of each. Species of the same element, or isotopes, in addition, differ from each other in mass or on the basis of the number of neutrons (neutral fundamental particles) in their nuclei. Nuclear species can be transformed into other nuclear species by reactions that add or remove protons or neutrons or both.

      Many of the chemical elements up to iron (atomic number 26) and their present cosmic abundances may be accounted for by successive nuclear fusion reactions beginning with hydrogen and perhaps some primeval helium. By repeated nuclear fusion, four hydrogen nuclei amalgamate into a helium nucleus. Helium nuclei, in turn, can be built up into carbon (three helium nuclei), oxygen (four helium nuclei), and other heavier elements.

      Elements heavier than iron and some isotopes of lighter elements may be accounted for by capture of successive neutrons. The capture of a neutron increases the mass of a nucleus; subsequent radioactive beta decay converts a neutron into a proton (with ejection of an electron and an antineutrino), leaving the mass practically unchanged. The increase in the number of protons builds the nucleus to higher atomic numbers.

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Universalium. 2010.

Look at other dictionaries:

  • nucleosynthesis — [no͞o΄klē ō sin′thə sis, nyo͞o΄klē ō sin′thə sis] n. [ NUCLEO + SYNTHESIS] the formation of heavier chemical elements from the nuclei of hydrogen or other lighter elements, as in the interior of a star …   English World dictionary

  • Nucleosynthesis — Nuclear physics Radioactive decay Nuclear fission Nuclear fusion Classical decays …   Wikipedia

  • nucleosynthesis — branduolių sintezė statusas T sritis chemija apibrėžtis Vienų atomų branduolių pavertimas kitais branduoliais. atitikmenys: angl. nuclear fusion; nucleosynthesis rus. синтез ядер; слияние ядер …   Chemijos terminų aiškinamasis žodynas

  • nucleosynthesis — branduolių sintezė statusas T sritis fizika atitikmenys: angl. nuclear fusion; nucleosynthesis vok. Kernfusion, f; Kernverschmelzung, f rus. синтез ядер, m; слияние ядер, n pranc. fusion nucléaire, f; nucléosynthèse, f …   Fizikos terminų žodynas

  • nucleosynthesis — noun Etymology: New Latin Date: 1960 the production of a chemical element from simpler nuclei (as of hydrogen) especially in a star • nucleosynthetic adjective …   New Collegiate Dictionary

  • nucleosynthesis — noun Any of several processes that lead to the synthesis of heavier atomic nuclei …   Wiktionary

  • nucleosynthesis — noun Astronomy the cosmic formation of atoms more complex than the hydrogen atom. Derivatives nucleosynthetic adjective …   English new terms dictionary

  • nucleosynthesis — nu·cleo·synthesis …   English syllables

  • nucleosynthesis — nu•cle•o•syn•the•sis [[t]ˌnu kli oʊˈsɪn θə sɪs, ˌnyu [/t]] n. astron. phs the formation of new atomic nuclei by nuclear reactions, as in stellar evolution • Etymology: 1955–60 nu cle•o•syn•thet′ic ˈθɛt ɪk adj …   From formal English to slang

  • nucleosynthesis — /ˌnjuklioʊˈsɪnθəsəs/ (say .nyoohkleeoh sinthuhsuhs) noun the synthesis of chemical elements by nuclear processes …   Australian English dictionary


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