History Stellar nucleosynthesis

in 1920 arthur eddington proposed stars obtained energy nuclear fusion of hydrogen form helium , raised possibility heavier elements produced in stars.

in 1920, arthur eddington, on basis of precise measurements of atomic masses f.w. aston , preliminary suggestion jean perrin, proposed stars obtained energy nuclear fusion of hydrogen form helium , raised possibility heavier elements produced in stars. preliminary step toward idea of nucleosynthesis. in 1928, george gamow derived called gamow factor, quantum-mechanical formula gave probability of bringing 2 nuclei sufficiently close strong nuclear force overcome coulomb barrier. gamow factor used in decade followed atkinson , houtermans , later gamow himself , edward teller derive rate @ nuclear reactions proceed @ high temperatures believed exist in stellar interiors.

in 1939, in paper entitled energy production in stars , hans bethe analyzed different possibilities reactions hydrogen fused helium. defined 2 processes believed sources of energy in stars. first one, proton–proton chain reaction, dominant energy source in stars masses mass of sun. second process, carbon–nitrogen–oxygen cycle, considered carl friedrich von weizsäcker in 1938, important in more massive stars. these works concerned energy generation capable of keeping stars hot. clear physical description of proton–proton chain , of cno cycle appears in 1968 textbook. bethe s 2 papers did not address creation of heavier nuclei, however. theory begun fred hoyle in 1946 argument collection of hot nuclei assemble iron. hoyle followed in 1954 large paper describing how advanced fusion stages within stars synthesize elements between carbon , iron in mass. dominant work in stellar nucleosynthesis. provided roadmap how abundant elements on earth had been synthesized initial hydrogen , helium, making clear how abundant elements increased galactic abundances galaxy aged.

quickly, hoyle s theory expanded other processes, beginning publication of celebrated review paper in 1957 burbidge, burbidge, fowler , hoyle (commonly referred bfh paper). review paper collected , refined earlier research heavily cited picture gave promise of accounting observed relative abundances of elements; did not enlarge hoyle s 1954 picture origin of primary nuclei as many assumed, except in understanding of nucleosynthesis of elements heavier iron. significant improvements made alastair g. w. cameron , donald d. clayton. cameron presented own independent approach (following hoyle s approach part) of nucleosynthesis. introduced computers time-dependent calculations of evolution of nuclear systems. clayton calculated first time-dependent models of s-process , of r-process, of burning of silicon abundant alpha-particle nuclei , iron-group elements, , discovered radiogenic chronologies determining age of elements. entire research field expanded rapidly in 1970s.

cross section of supergiant showing nucleosynthesis , elements formed.