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Alessandro Chieffi

The synthesis of 26 Al, 60 Fe and 44 Ti in massive stars and their current inventory in our Galaxy. Alessandro Chieffi Istituto Nazionale di AstroFisica (Istituto di Astrofisica e Planetologia Spaziale) & Centre for Stellar and Planetary Astrophysics – Monash University - Australia

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Alessandro Chieffi

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  1. The synthesis of 26Al, 60Fe and 44Ti in massive stars and their current inventory in our Galaxy Alessandro Chieffi Istituto Nazionale di AstroFisica (Istituto di Astrofisica e Planetologia Spaziale) & Centre for Stellar and Planetary Astrophysics – Monash University - Australia Email: alessandro.chieffi@iaps.inaf.it In collaboration with Marco Limongi Dust in EuroGENESISenvironments: from primitive, massive stars to novaePerugia (Italy), November 11-14, 2012

  2. Na22 2.6 Yr 2.842 MeV Ti44 63 Yr 0.268 MeV Sc44 3.9 h 3.653 MeV Ni56 5.9 d 2.135 MeV Co56 77 d 4.566 MeV Co57 271 d 0.836 MeV

  3. SMM GRIS Between 1979 and 2001 several experiments were carried out: CGRO HEAO3 R. DIEHL Clemson 2005 Astronomy with Radioactivities V Kretschmer et al. AA 412,47 (2003)

  4. On the basis of just the integrated flux towards the galactic center, the various 26Al sources are: 10<M<30 Type II Supernovae Confined in the spiral arms of our Galaxy 30<M<120 WR stars Novae Confined within the disk of our Galaxy 1-3<M<7 Intermediate mass stars

  5. Kretschmer et al. AA 412,47 (2003) Plüschke et al. AIP Conf. Proc. 510 ed. M.L. McConnell & J.M. Ryan p 35-39 (2000)) 1.809 MeV All Sky Map CGRO

  6. The 53 GhZ free-free all-skymapmarks the regions of ionizedmatter. A strong ionizing flux (l<912 A) is necessary to mantain matter ionized (otherwise it would recombine in 1 Myr) Only stars more massive than, say, 15 MO do produce a strong ionizing flux hence The correlationbetween the 53 GhZ free-free and the 1.809 MeVmapsimpliesthatthey share the samespatialdistribution and thereforethat26Al and ionizingphotons are produced by the samestars i.e. 26Al mainly produced by stars more massive than 15 MO Knodelseder (1999 - ApJ 510, 915) found also that the scaling between the two fluxes is CONSTANT towards all longitudes and equal to: Y26Al = 10-4 MO per O7 V (Log(Qo)=49.05) RGxL = 1.25 10-11g1.8MeV / g<912A

  7. RHESSI and INTEGRAL launched in 2002 Reuven Ramaty High Energy Solar Spectroscopic Imager INTErnational Gamma-Ray Astrophysics Laboratory R. DIEHL Clemson 2005 Astronomy with Radioactivities V R. DIEHL Clemson 2005 Astronomy with Radioactivities V 60Fe/26Al RHESSI 0.17± 0.05 INTEGRAL 0.14± 0.03 Diehl et al. (2006 – Nature 439,5)

  8. Summary of the observational facts: 1) 26Al is very probably produced by stars having M>15 MO 2) There are roughly 1.25 10-11g1.8MeV per ionizing photon at all longitudes 3) The 60Fe/26Al flux ratio is of the order of 0.14 ± 0.05 towards the Galactic center 4) Roughly 2.8 MO of 26Al are present in the Galaxy (± 30%)

  9. The theoretical interpretation is based on our database of evolutions of massive stars: Limongi and Chieffi (2006 – ApJ 647, 483) FRANEC (release 5.050419) O.R.F.E.O. OnlineRepository for theFranecEvolutionary Output WEBPAGE: http://orfeo.iasf-roma.inaf.it WARNING: though the ground and the metastable 26Al states are properly taken into account, for simplicity in the following I’ll simply refer to the total 26Al

  10. H rich mantle Central H burning He burning shell He core C convective shell CO core Fe Shock wave Si burning shell 26Al production: 1) H convective core 2) C (Ne/C) conv. shell (when the star is in shell Si burning) 3) Explosive Ne burning

  11. H rich mantle Central H burning 26Al production in central H burning 28Si 29Si 26Al 27Al P 24Mg 25Mg 26Mg N The 25Mg is the initial one (usually scaled solar)

  12. He core CO core Fe DESTRUCTION: C profile X produced preserved 26Al 22Ne,12C M 26Al production in the C (Ne/C) convective shell 28Si 29Si 26Al 27Al P 24Mg 25Mg 26Mg N (CNO)INI Þ14N(a,g)18F(b+)18O(a,g)22Ne(a,n)25Mg 12C(12C,a)20Ne 12C(12C,p)23Na(a,p)26Mg

  13. 26Al production in C (Ne/C) convective shell

  14. He core CO core Fe T2 T1 Fe core r1 r2 Shock wave ignition 26Al production by the explosive Ne burning The synthesis of 26Al occurs in the region where the peak temperature drops to Tpeak» 2.2 109 K 28Si 29Si 26Al 27Al P (n,p) 24Mg 25Mg 26Mg 23Na N

  15. Total 26Al yield as a function of the initial mass

  16. Diehl et al. (2006 – Nature 439,5)

  17. By adopting: mup’ =11MO – Mtop = 120MO a Galactic Lyman continuum Luminosity QGAL= 3.5 1053 photons/s The galactic RGxL The galactic 26Al

  18. The galactic 26Al By adopting: mup’ =11MO – MSN I I =35MO – Mtop = 120MO a Galactic Lyman continuum Luminosity QGAL= 3.5 1053 photons/s Steady state

  19. g2 Velorum Binary system containing the closest WR(11) star Main data taken from Schaerer et al. (1997) and Oberlack et al. (2000) Distance: 258 pc - WC8 (9 MO) - O8.5III (29 MO) 26Al(Upper limit) => 6.3 10-5 (+2.1-1.4) MO

  20. g2 Velorum Binary system containing the closest WR(11) star Main data taken from Schaerer et al. (1997) and Oberlack et al. (2000) Distance: 258 pc - WC8 (9 MO) - O8.5III (29 MO) 26Al(Upper limit) => 6.3 10-5 (+2.1-1.4) MO

  21. 60Fe production: 1) basics 60Ni 58Ni 61Ni 62Ni 59Co P 56Fe 57Fe 58Fe 60Fe 59Fe 44 d N 22Ne(a,n)25Mg Main n donor Central He burning rcrit = 1010 n/cm3 r < 107 n/cm3 T < 3.5 108 K r = few 107 n/cm3 rcrit = 3 1011 n/cm3 Central C burning T < 109 K r => 6 1010 to 1012 n/cm3 Shell He burning T > 4 108 K r => 6 1011 to 2 1012 n/cm3 Shell C burning T > 1.3 109 K r => 6 1011 to 2 1012 n/cm3 Shell Ne burning T > 1.8 109 K

  22. He/C X produced preserved 60Fe 22Ne,12C M 60Fe production: 2) the He and C convective shells

  23. 60Fe production: 3) the Ne explosive contribution

  24. The total60Fe production M < 60 MO Mainly produced by the C convective shell M > 60 MO Mainly produced by the C convective shell (Ledoux criterion) M > 60 MO Mainly produced by the He convective shell (Schwarz. criterion)

  25. The galactic 60Fe/26Al flux ratio The 60Fe/26Al flux ratio is of the order of 0.14 ± 0.03 towards the Galactic center

  26. Summary & Conclusions • Observational: • 26Al is very probably produced by stars having M>15 MO • There are roughly 1.25 10-11 n(g1.8MeV)/ (ionizing photon) at all longitudes • The 60Fe/26Al flux ratio is of the order of 0.14 ± 0.05 towards the Galactic center • Roughly 2.8 MO of 26Al are present in the Galaxy (± 30%) • Theoretical: • 26Al is mainly produced by the Ne explosive burning. • 60Fe is mainly produced by the C convective shell. • The observed (and quite constant) average number of g1.8MeV per ionizing photon (RGxL) is rather well reproduced by our models. • The observed 60Fe/26Al flux ratio towards the center of our Galaxy is well reproduced if the Langer (1989) mass loss rate in the WNE,WCO is adopted. • Our predictions for g2 Velorum are in agreement with the quoted upper limit and hence the longstanding discrepancy between the data and the predictions is removed.

  27. Cas A as seen by IBIS – ISGRI aboard INTEGRAL at 25 - 40 KeV Distance 3 Kpc -- 335 yrold -- Mini 30 MO Mend 16 MO 3 lines : 67.9 KeV, 78.4 KeV, 1.157 MeV t(44Ti)= 59.8 yr Observed: M(44Ti)=1.6 10-4 MO Predicted: M(44Ti)= 3 10-5 MO

  28. 44Ti Produced in the a-rich freeze-out of zones exposed to the complete explosive Si burning Not produced in a normal freeze out tcooling << tbuild up tcooling >> tbuild up ( 3a => 12C(a,g)16O(a,g)...NSE ) Critical phase

  29. 55Mn 52Cr 53Cr 50Cr 54Cr 50V 51V 49Ti 50Ti 44Ti 46Ti 47Ti 48Ti 45Sc 40Ca 42Ca 43Ca 44Ca 46Ca 48Ca Produced in the a-rich freeze-out of zones exposed to the complete explosive Si burning 44Ti 40Ca(a,g)44Ti 44Ti(a,p)47V 43Sc(p,g)44Ti 41Ca(a,n)44Ti 44Sc(p,n)44Ti

  30. 26Al production in central H burning: 1) basics 28Si 29Si 26Al 27Al P 24Mg 25Mg 26Mg N

  31. 26Al production by the explosive Ne burning: 1) basics 28Si 29Si 26Al 27Al P (n,p) 26Al(n,p) CA88 26Al(n,a) NACRE 24Mg 25Mg 26Mg 23Na N

  32. 26Al production in central H burning: 3) uncertainties many...., but we tested the following: 1) the initial 25Mg abundance 2) the 25Mg(p,g)26Al cross section 3) the convective core size

  33. 26Al production in central H burning: 3) uncertainties 60 MO STD 6.94 10-5 25MgINI*2 1.39 10-4 1) the initial 25Mg abundance 2) the 25Mg(p,g)26Al cross section 120 MO 60 MO STD 2.82 10-4 MO 0.5 HP 3.50 10-4 MO STD 6.94 10-5 MO 0.5 HP 5.98 10-5 MO 3) the convective core size (0.3 Hp )

  34. 26Al production by the explosive Ne burning: 4) uncertainties 28Si 29Si 26Al 27Al P (n,p) 24Mg 25Mg 26Mg 23Na N 20Ne(g,a)16O 20Ne(a,g)24Mg 20Ne(a,p)23Na 24Mg(a,p)27Al

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