1. Nucleosynthesis and formation of the elements

2. Cosmic abundance of the elements Mass number

3. Nucleosynthesis Big Bang – ca 12 000 Ma Supernova – ca 5 000 Ma Condensation of matter and formation of the known elements...

4. In the seconds following the Big Bang Condensation of matter into p and e – Formation of the fuel of the stars... H et He T  3 x 10 9 K p + e –  n + v 1 H + n  2 H +  2 H + p  3 He +  3 He + n  4 He + 

6. Diagramme Hertzprung-Russel

7. 1 st Generation Stars - H fusion and production of 4 He 1 H + 1 H  2 H +  + + v0.422 MeV0.422 MeV 2 H + 1 H  3 He +  5.493 MeV5.493 MeV 3 He + 3 He  4 He + 1 H + 1 H12.859 MeV12.859 MeV

8. 2 nd Generation Stars (Our sun today) Fusion by CNO reaction 12 C + 1 H  13 N +  13 N  13 C +  + + v 13 C + 1 H  14 N +  14 N + 1 H  15 O +  15 O  15 N +  + + v 15 N + 1 H  12 C + 4 He

9. He Fusion in Red Giants (~ 10 6 to 10 7 years) 4 He + 4 He  8 Be 8 Be + 4 He  12 C +  12 C burning (<1000 years) 12 C + 4 He  16 O 12 C + 12 C  20 Ne + 4 He +  16 O burning (<1 year) 16 O + 16 O  28 Si + 4 He +  12 C + 16 O  24 Mg + 4 He + 

10. End of a Red Giant's life: Si combustion: lasts about 1day 28 Si + 4 He  32 S +  32 S + 4 He  36 Ar +  36 Ar + 4 He  40 Ca +  40 Ca + 4 He  44 Ti +   44 Ca + 2   44 Ti + 4 He  48 Cr +  48 Ti + 2   48 Cr + 4 He  52 Fe  52 Cr + 2   52 Fe + 4 He  56 Ni +  56 Fe + 2   56 Ni / 56 Fe + 4 He  impossible...

11. Nuclear binding energy maximum maximum at 56 Fe after, fusion becomes endothermic nucleosynthesis beyond 56 Fe is by neutron capture and by fission of nuclides with Z > 90 (uranium and transuranics) http://www.chem.uidaho.edu/~honors/nucbind.html

12. Supernova and 2 nd generation stars

13. Supernova remnants Cas A in x-rays (Chandra) Vela SN1998bu Remnant of SN386, with central pulsar (Chandra) Cygnus Loop (HST): green=H, red=S +, blue=O ++

14. Nucleosynthesis by n and p capture

15. Fe: produced in the final stage of fusion Elements > Fe: neuton activation in supernova Instable CNO Fissionable Elements F Na Mg Cl Al P K Ar V Ti Cr Mn Co Equilibrium burning