The Origin of Elements: A Tale of Red Giants and Supernovae

1. The Origin of the Elements – a story of Red Giants and Supernovae I it all began not so longago… an historicalintroduction II nucleosynthesis from the Big Bang until today IIIfromFe to the actinides by neutron capture reactions

2. nucleosynthesis 1900 ?

3. spectral linies – abundance messages from space

4. milestones of nucleosynthesis 1937first table of solar abundances by Goldschmidt 1937 - pp chain and CNO cycle identified as stellar energy sources by Bethe & Critchfield and by von Weizsäcker 1940ies initial ideas about Big Bang and CMB formulated by Gamow et al. 1952discovery of Tc in Red Giant stars by Merrill: evidence for stellar nucleosynthesis 1957fundamental papers on nucleosynthesis by Burbidge, Burbidge, Fowler & Hoyle (B2FH) Rev. Mod. Phys. 29, 547 (1957) Cameron Pub. Astron. Soc. Pacific 9, 201 (1957) 39

5. sources of abundance information Meteorites stone iron carbonaceous chondrites ±10% ±1%

6. s r abundances beyond Fe – ashes of stellar burning and SNe Neutrons Fusion BB Fe H 30 000 C 10 Fe 1 Au 2 10-7 abundance s r mass number neutrons produce 75% of the stable isotopes, but only 0.005% of total abundances

7. 1957: nucleosynthesis concepts Al Cameron Burbidge, Burbidge, Fowler, Hoyle

8. Big Bang t = 0.5 – 200 s: thermal equilibrium, nn/np = e−Q/kT = 1/7 at T>1 GK t = 200 – 1000 s: nucleosynthesis of d, t, 3He, 4He, 7Li 7Li Xpred = (1.5 ± 0.2) 10-9 4He (n, a)a Xpred∼ (2n+2p) +12 p 0.25 by mass Xobs ∼ (3–7) × 10−10 (n, p) Xobs = 0.248±0.003 the cosmological Li problem remains unsolved

9. nucleosynthesis: stars or BB? Merrill 1952: discovery of Tc lines in spectra of Red Giants all Tc isotopes unstable (t1/2<4 Myr) proof of stellar origin

10. further evolution

11. convection zone radiation zone main sequence abundances by H fusion surface composition not affected H 4He CNO 14N H He

12. H burning: pp chain and CNO cycle wikimedia.org

13. Coulomb barrier, cross section, S factor, Gamow window Rolfs & Rodney, Fig 4.2

14. S factor and solar Gamow window 3He(a, g) 14N(p, g) Takacs et al. (2015): 0.54±0.054  keV b 0.1 1 Ecm (MeV) 0.01 0.1 1 Ecm (MeV) ʘ BB

15. Hertzsprung-Russell diagram (1913) LUMINOSITY SURFACE TEMPERATURE

16. Fred Hoyle and the triple-a-process 1953: based on the observed carbon abundance Hoyle postulates a nuclear state in 12C at 7.68 MeV; the Hoyle state was promptly confirmed experimentally at CalTech Zentrum Dunbar et al. Phys. Rev. 92, 649 (1953): „… we find the energy of excitation in 12C to be 7.68±0.03 MeV.“ wikimedia.org

17. late stages of stellar evolution planetary nebula oder supernova? from ESO

20. Konvektive Hülle He burning in low-mass stars (<8Mʘ) element production and transport to surface H He-shell burning Tc! He 4He, 12C, 14N, 16,18O 22Ne, 25,26Mg and main s-process contributes to most isotopes from Fe to Pb/Bi 13C(a,n) convective envelope C/O

21. s-process enriched envelope ejected in stellar wind and as planetary nebula

22. s-process signature s N ≈ const CROSS SECTION x ABUNDANCE (Si=106) MASS NUMBER

23. Konvektive Hülle H → He: 7 Myr He → C, O: 0.700 Myr C → Ne, Mg: 600 yr Ne → O: 1 yr O → Si: 0.5 yr Si → Ni: 1 d massive stars (>8Mʘ) H He C Ne O Si Fe/Ni fusion: C- Fe weak s process: Fe – Zr 22Ne(a,n) collapse of Fe/Ni core triggers supernova r process? Fe to actinides?

24. Nr = N - Ns r-process residuals

25. Crab nebula: typical supernova remnant no or very little r process

26. classical nucleosynthesis in supernovae: rand p process np process p process r process ?

27. p process abundances with 2D model of core collapse SNe : 20 Mʘ deficits below A~120 25 Mʘ Pignatari et al. 2016 https://arxiv.org/abs/1605.03690

28. np process works below A~120 Martinez-Pinedo, Physik Journal 7, 51 (2008)

29. weak r process in rare, fast rotating stars ?

30. r process observed in early GCE • oldest stars (Z = 10-4 Zʘ) show r-process pattern from Ba to Pb identical with solar r abundances log ABUNDANCE observed scaled solar system ATOMIC NUMBER two r-processes?

31. neutron star mergers: another site for the r process Hulse-Taylor-Pulsar PSR 1913+16 orb. period: 147 min distance: 3 Ls (1 000 000 km) rot. period: 23 ms & 2.8 s masses: 1.34 & 1.25 Mʘ time dilatation: 0.4 ms life time: 300 Myr ± 0.03%

32. neutron star merger simulation Rosswog et al., Class. Quantum Gravity 34, 104001 (2017) D. Martin et al., Phys. Rev. Lett. 116, 121101 (2016)

33. August 17 2017: multi-messenger data of GW170812 Abbott et al. Ap.J.Lett 848 (2017) L12

34. stellar evolution in a nutshell 0.1 M 1 M 4 10 Gyr, Fe seed 10 M 1 Myr, no seed required 100 M

35. ca.10 Gyr ca. 10 Myr star formation rate 4 stellar masses s-process late contribution r-process, C - Fe first metals