Cosmological nucleosynthesis and abundances of light elements

But the helium which we handle must have been put together at some time and some place. We do not argue with the critic who urges that the stars are not hot enough for this process we tell him to go and find a hotter place. 

The Hot Big Bang theory of the Universe was pioneered by George Gamow, R. A. Alpher and R. C. Herman in the late 1940s and early 50s. They supposed that during the first few minutes of the (then radiation-dominated) Universe, matter was originally present in the form of neutrons and that, after some free decay, protons captured neutrons and successive captures, followed by /3-decays, built up all the elements (Alpher Herman 1950). 

1 Apart from improved calculations of the primordial helium abundance by Alpher, Follin and Herman (1953) and in a prescient paper by Hoyle and Tayler (1964). 

Schramm, G. Steigman and others, which assumes standard cosmology and particle physics and a uniform baryon density, has been very successful in several respects, e.g.  

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Big efforts have been devoted in the last years to the study of light elements abundances. Definitively their importance is strongly related to cosmology as well as to stellar structure and evolution. In fact hints on the primordial nucleosynthesis can be achieved from Li, Be and B primordial abundances. Moreover these studies can be a precious tool for testing and understanding the inner stellar structure, especially for what regards the mixing processes in stellar envelopes [11-... 

The molecules found to date are composed of the elements H, C, N, O, Si, S, and Cl with the bulk of the molecules containing H, C, N, and O. The light elements H, D, and He are of cosmological origin and are therefore tracers of the early universe. On the other hand the heavier elements C, N, O,... are produced in stars by the processes of stellar nucleosynthesis. In addition to the most abundant isotopic forms many stable isotopes such as D, 13C, 170, lsO, 15N, 30Si, 33S, and 34S have been detected (see Appendix 1). The detailed determination of isotopic ratios — though often beset with formidable difficulties — has become a useful indicator of the chemical evolution of molecular clouds and the past chemical history of the galaxy. 

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