Light elements primordial

As a summary of several studies for light elements in unevolved cluster stars (based on photometric or low dispersion spectroscopic indexes), the right panel of Fig. 1 nicely shows the main features. There are star-to star abundance variations, with large spreads in N anticorrelated with much smaller spreads in C (as found all the way from MS to RGB). The implications are that we are not looking simply at a conversion of C into N, and that primordial inhomogeneities... 

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 crucial species in primordial nucleosynthesis of the light elements is helium. There are two reasons ... 

In this chapter we will first consider the underlying information on the elemental abundances and some of the implications of the isotopic abundances. Then, we will consider the nuclear processes that took place to produce the primordial elements and those that processed the primordial light elements into those that we have here on Earth. 

The agreement between the predictions of the SBBN model for the abundances of deuterium, helium-4, helium-3 and lithium-7 and the observations of the primordial abundances of these light elements is one of the successes and therefore one of the cornerstones of the Big Bang Cosmology. 

The primordial abundances of the light elements are not measured easily and simultaneously. The main difficulties come from systematic uncertainties in inferring abundances from observations and in modeling their chemical evolution since the Big Bang. 

In the first chapter of this book, deuterium was identified as having originated moments after the big bang thus, deuterium is primordial in character. This raises an important question Can the currently observed amount of deuterium in the universe become another empirical check on big bang cosmology More specifically, can the nuclear synthesis of the light elements—mostly helium ( He) plus mere traces of deuterium ( H), hehum ( He), and lithium ( Li)— which occurred over a brief period soon after the big bang itself, account for their currently observed abundances ... 

Cyburt R. H., Eields B. D., and Ohve K. A. (2002) Primordial nucleosynthesis with CMB inputs probing the early universe and light element astrophysics. Astropart. Phys. 17, 87—100. 

When nucleosynthesis begins, nearly all the surviving neutrons end up bound in the most stable light element " He. Heavier nuclei do not form in any significant quantity both because of the absence of stable nuclei with mass number 5 or 8 (which impedes nucleosynthesis via " He + n, " He + p or " He + " He reactions) and the large Coulomb barriers for reactions such as the T + " He 7 + Li and He + " He 7 + Be reactions listed above. Hence the primordial mass fraction of " He, conventionally referred to as Yp, can be estimated by the simple counting argument... 

BBN theory predicts the universal abundances of (D), He, " He, and Li, which are essentially determined by / 180 s. Abundances are however observed at much later epochs, after stellar nucleosynthesis has commenced. The ejected remains of this stellar processing can alter the light element abundances from their primordial values, but also produce heavy elements such as C, N, O, and Fe ( metals ) Thus one seeks astrophysical sites with low metal abundances, in order to measure light element abundances which are closer to primordial. For all of the light elements, systematic errors are an important and often dominant limitation to the precision of the primordial abundances. 

Figure 9. Primordial light element abundances as predicted by BBN and WMAP (dark shaded regions) [104], Different observational assessments of primordial abundances are plotted as follows (a) the light shaded region shows D/H = (2.78 0.29) x 10 (b) the light shaded region shows Yp = 0.249 0.009 (c) the light shaded region shows i/H =1.23lo i6 10 while the dashed curve shows i/H = (2.19 0.28) x. ...

Helium is the second most abundant element in the universe (76% H, 23% He) as a result of its synthesis from hydrogen (p. 9) but, being too light to be retained by the earth s gravitational field, all primordial helium has been lost and terrestrial helium, like argon, is the result of radioactive decay ( He from a-decay of heavier elements, " °Ar from electron capture by... 

To quote the words of Professor Collie— We are possibly dealing with the primordial form of matter, the primordial atom, which when produced had all the energy necessary for forming the world. By combination of these atoms the atoms of elements could be formed. Possibly the electric current directed the flow of these atoms with the full force of its energy, and with the phenomena of heat and light the elements came into existence. (1913, 146)... 

Therefore, you must be mindful in the new microcosmic Creation, that is, in the Magnum Opus of the Sages, that all Elements of our Subjecti, as well as the lower and the upper (Light, Air, Water, Earth, Fire, fleeting and fixed Spiritum) be made into a philosophical Water, or respectively into Wine, in which Light and Darkness, Death and Life are together, as it was in the primordial Chaos of Creation. 

The light and fragile elements lithium, beryllium, and boron (LiBeB) are not primarily produced in primordial or stellar nucleosynthesis. In fact, the abundance curve in O Fig. 12.13 shows a huge dip (almost a gap, actually) for the mass numbers 8-11, reflecting the scarcity of LiBeB-nuclei in the solar system. Only the nuclide Li can be produced both in primordial (see Sect. 12.3) and in stellar nucleosynthesis (see Sect. 12.4.2), whereas the nuclides Li, Be, B, and B are almost pure spallation products of heavier elements. 

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