1.  Nucleosynthesis:  Elemental abundance in solar system From http://en.wikipedia.org/wiki/File:SolarSystemAbundances.png

2.  Characteristics of the elemental abundance 1. H & He are the two elements most abundant. H/He=12.5 2. The abundance decreases exponentially up to Z=50 3. Elements z>50 are very low, their abundance shows relatively little changee as a function of Z 4. “Oddo-Harkins rule” for Z>5 5. The abundances of Li, Be, & B are extremly low 6. Fe is prominently high w/r to other neighbors 7. 43 Tc & 61 Pm are missing 8. Elements Z>83 (Bi) are very rare & unstable   All these characteristics can be xplained with nucleosynthesis

3.  Nucleosynthesis 1. H-burning, T>10 7 K, d> 100 g/cm 3 1 H(p, e + n) 2 D (e +, e - ) (annihilation) 2 D(p, g) 3 He 3 He( 3 He, 2p) 4 He 2. Synthesis with intermediate nuclei 7 Be(e -, n) 7 Li 7 Li(p, g) 8 Be 8 Be --> 2 4 He Or 7 Be(p, g) 8 B 8 B --> 8 Be + e - + n 8 Be-->2 4 He

4. 1. CNO cycle, T<10 8 K 12 C(p, g) 13 N --> 13 C + e - + n 13 C(p, g) 14 N 14 N(p, g) 15 O --> 15 N + e - + n 15 N(p, a) 12 C 16 O(p, g) 17 F --> 17 O + e - + n 17 O(p, a) 14 N 2. Helium-burning, T~ 10 8 K, d~ 10 5 g/cm 3 4 He + 4 He --> 8 Be 8 Be(a, g) 12 C 12 C(a, g) 16 O 16 O(a, g) 20 Ne 20 Ne(a, g) 24 Mg

5. 3. C- & O-burning, T>8*10 8 K 12 C( 12 C, p) 23 Na 12 C( 12 C, a) 20 Ne 12 C(p, g) 13 N --> 13 C + e - + n 13 C(a, n*) 16 O T>2*10 9 K 16 O( 16 O, n*) 31 S 16 O( 16 O, p) 31 P 16 O( 16 O, a) 28 Si T>2.5*10 9 K 31 P(g, p) 30 Si 30 Si(g, n*) 29 Si 29 Si(g, n) 28 Si

6. 4. E-process (equilibrium p-) Silicon-burning Equilibrium between P & N Element 28<Z<57 5. S- & r-process (slow- & rapid-p-) Neutron capture  isotopes S-; Z<209 (Bi) R-; Z>209 6. P-process: T>3*10 9 K 7. X-process: spallation of nucleus

7. From http://ned.ipac.caltech.edu/level5/Pagel/Figures/figure1_5.jpeg