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The role of (some) nuclear reaction rates in the evolution of the stars of low, intermediate and high mass

The role of (some) nuclear reaction rates in the evolution of the stars of low, intermediate and high mass. Alessandro Chieffi (Istituto di Astrofisica Spaziale e Fisica Cosmica & INAF) Email: achieffi@rm.iasf.cnr.it. 25 M O. 5 M O. 1 M O. REMEMBER that:

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The role of (some) nuclear reaction rates in the evolution of the stars of low, intermediate and high mass

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  1. The role of (some) nuclear reaction rates in the evolution of the stars of low, intermediate and high mass Alessandro Chieffi (Istituto di Astrofisica Spaziale e Fisica Cosmica & INAF) Email: achieffi@rm.iasf.cnr.it

  2. 25 MO 5 MO 1 MO

  3. REMEMBER that: The interplay between the evolution of a star and the nuclear processes occurs through the RATES and NOT the cross sections: Rlk => Xl x Xk x screening x <sv>lk

  4. 25 MO Dt(H-burn)= - 0.3% M(He) => 8.3 to 8.6 MO CNO cycle <sv>3a x 10 is NOT appreciable 14N(p,g)15O x 10 5 MO CNO cycle M(He) => 0.91 to 0.97 MO Dt(H-burn)= - 4% 1 MO PP chain p(p,e+n)d Dt(H-burn)= - 3%

  5. HB RGB TO MS

  6. Z=10-4 Y=0.23 Solid => reference Dashed => (14N(p,g)15O) / 2 10 Gyr 13 Gyr

  7. M=0.8 MO Y=0.23 Z=10-4 Red – reference Blue – 14N(p,g)15O / 2 • MHe = 1% • Mbol(tip) = 0.055 Mag -0.04 Mag => - 0.6 Gyr

  8. AGB phase 0.7 < M / MO < 7 He burning shell R(Hshell) ~10-5 Rstar CO core He (+C) intershell Neutron production s process nucleosynthesis H burning shell H-rich mantle

  9. Convective envelope H shell M(MO) He shell t(yr)

  10. Convective envelope H shell M(MO) He conv. shell He shell t(yr)

  11. -1 8.5 7.5 Base conv. env. H burn. shell He burn. shell Log(Surf. C abund.) Log(Tmax He shell) Log(T base conv. Env.) -3 8.1 6.5

  12. He luminosity

  13. M=3 MO Z=0.02 Y=0.284 Network: H to Si (full) + Neutron captures on: Fe Kr84 – Rb – Sr – Y – Zr92 Xe132 – Cs – Ba – La – Ce – Pr – Nd144 Hg202 – Tl – Pb – Bi209 92 nuclei

  14. Log10(PF) Element

  15. Log10(PF) Stable Isotopes

  16. M=3 MO - Z=0.02 Reference 3a / 2 3a x 2 14Npg / 2

  17. SURFACE CARBON ABUNDANCE Reference 3a / 2 3a x 2 14Npg / 2

  18. The mother of all rates: 12C(a,g)16O

  19. Roadmap... 1) WR stars: evolution & explosive nucleosynthesis 120 35 2) Intermediate Mass Stars: elemental yields

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