1. The massive zero metal stars: their evolutionary properties and their explosive yields. Alessandro Chieffi Istituto Nazionale di AstroFisica (Istituto di Astrofisica Spaziale e Fisica Cosmica) & Centre for Stellar and Planetary Astrophysics – Monash University - Australia Email: achieffi@rm.iasf.cnr.it Marco Limongi Istituto Nazionale di AstroFisica (Osservatorio Astronomico di Roma) & Centre for Stellar and Planetary Astrophysics – Monash University - Australia Email: marco@mporzio.astro.it INAF

2. The “metallicity” influences the physical evolution of a star: CNO T of H burning Fe +  elements  (opacity) ZERO METALLICITY STARS FREQUENTLY SHOW THE MERGING OF THE H AND HE RICH LAYERS! Mass Loss depends on Z

3. Log 10 (X) M(M O ) 7.5 8.5 Log 10 (T)

4. The “metallicity” influences the yields provided by a star: CNO 25 Mg & n Initial isotopic distribution (seeds) Odd-even effect Neutron excess  (affects the explosive burnings) The weak s-component

6. 12 C 13 C 14 N 15 N 16 O 17 O 18 O 19 F 20 Ne 21 Ne 22 Ne 23 Na 24 Mg 26 Mg 25 Mg 27 Al 28 Si 30 Si 29 Si 31 P 32 S 33 S 34 S 35 Cl 36 S 37 Cl P N

7. 12 C 13 C 14 N 15 N 16 O 17 O 18 O 19 F 20 Ne 21 Ne 22 Ne 23 Na 24 Mg 26 Mg 25 Mg 27 Al 28 Si 30 Si 29 Si 31 P 32 S 33 S 34 S 35 Cl 36 S 37 Cl P N

9. Co Cu Zn Sc Ti Fe Ni Z=0 Z=Z O

10. 131520253035

11. The theoretical yields Presupernova evolution computed with the FRANEC (rel. 4- 05.04.19) Nuclear network of 296 nuclei (complete up to Mo) Two alternative set up: Physical + Chemical equations solved simultaneously mixing performed in a successive step through a diffusion equation or Physical equations solved first Local burning and mixing fully coupled together Grid of 8 stellar models: 13, 15, 20, 25, 30, 35, 50 and 80 M O initial chemical composition: Z=0, Y=0.23 Explosive yields computed by means of a PPM code The energy is injected by imposing an arbitrary velocity to a few mass layers around 1M O

12. N strongly produced in the range 25 to 40 M O (it depends significantly on the amount of C left by the He burning) All these yields have been obtained for a specific choice of the Mass Cut Yields often do not show a monotonic dependence on the initial mass [Al/O] in principle could be a initial mass indicator Hydrostatic burn. O x & Si ix O x Si x & Si ix Si x Si ix

16. Mass cut 0.1 56 Ni Variable Mass cut

18. CONCLUSIONS DON’T MISS THE NEXT TALK!