Cosmic abundance curve

Schematic representation uf the main features of the curve of cosmic abundances shown in Fig. 1.1, labelled according tn the various stellar reactions considered to be re.sponsible for the synthesis of the elements. (After E. M. Burbidge et...

Cosmic abundances of elements and isotopes Table 3.3. Exponential curves of growth... 

FIGURE 17.11 The variation in cosmic nuclear abundance with atomic number. Note that elements with even atomic numbers (brown curve) are consistently more abundant than neighboring elements with odd atomic numbers (blue curve). 

Fig. 9.7. Evolution of Be and B abundances according to the model based on confinement of cosmic rays in the early Galaxy (solid curves). Some observational data points are shown with error bars. Adapted from Prantzos, Casse and Vangioni-Flam (1993).

The cross section obtained for single fullerenes and buckyonions reproduce the behaviour of the interstellar medium UV extinction curve. A power-law size distribution n(R) R m with in = 3.5 1.0 for these molecules can explain the position and widths observed for the 2,175 A bump and, partly, the rise in the extinction curve at higher energies. We infer ISM densities of 0.2 and 0.1 ppm for small fullerenes and buckyonions (very similar to the densities measured in meteorites). If as expected the cosmic carbon abundance is close to the solar atmosphere value, individual fullerenes may lock up 20-25% of the total carbon in the diffuse interstellar space. 

Figure 6. Atmospheric concentrations as functions of the radiogenic noble gases Ar, Kr, and Kr and of the man made traces gases CFC-11, CFC-12, and SFe. Concentrations are normalized to the respective atmospheric abundances in 1998. In addition a typical (input) curve of in precipitation is shown. Note, nuclear bomb tests in the atmosphere increased the global tritium inventory by up a factor of 1000. Since then concentrations steadily decreased, but still today tritium activity in young meteoric waters is commonly one order of magnitude larger than the natural background due to cosmic rays production.

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