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AGB and stardusts

AGB and stardusts. Roberto Gallino A. Davis, Enrico Fermi Institute, Chicago M. Lugaro, Institute of Astronomy, Cambridge (UK) M. Pellin, Argonne National Laboratory, (USA) E. Zinner, Washington Univ., St. Louis (USA) M. Pignatari, Torino Univ. O. Straniero, Teramo Obs.

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AGB and stardusts

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  1. AGB and stardusts Roberto Gallino A. Davis, Enrico Fermi Institute, Chicago M. Lugaro, Institute of Astronomy, Cambridge (UK) M. Pellin, Argonne National Laboratory, (USA) E. Zinner, Washington Univ., St. Louis (USA) M. Pignatari, Torino Univ. O. Straniero, Teramo Obs. V Riunione Nazionale di Astrofisica Nucleare, Teramo 20-22 Aprile 2005

  2. AGB stars

  3. 1010 107 Wasserburg, Busso and Gallino 1999 ARAA

  4. Reproduction of Solar Main Component by post-processing method (Gallino et al. 1998) • 13C-pocket: • artificially introduced • ad hoc modulated • constant Pulse by Pulse

  5. Grains from AGB stars

  6. Murchison CM chondrite

  7. Presolar stellar grains journey from their site of formation around stars to our laboratories.

  8. central star ~ 1011 m, ring ~ 1016 m 1 m But careful with the dimensions! 10-6m

  9. Zr

  10. Lugaro et al., 2003, ApJ

  11. Lugaro et al., 2003, ApJ

  12. Mo

  13. Lugaro et al., 2003, ApJ

  14. Lugaro et al., 2003, ApJ

  15. Sr

  16. Nicolussi et al., 1998, PRL Lugaro et al., 2003, ApJ

  17. Ru & Tc

  18. Ru in mainstream SiC grains Comparison with AGB stellar models

  19. Grains formed while 99Tc (T1/2=213 ky) was still alive • Tc seen in red giant stars, which pointed to them as the source of the s-process • Tc-Ru isotope story in SiC grains cements the connection of mainstream SiC grains with AGB stars, the major site of the s-process Savina et al., 2003, Science

  20. Predicted Fe composition Very hard to measure: Fe/Si in SiC ~ 10-3 Solar within uncertainties in 4 SiC grains, using nanoSIMS

  21. SiC-X grains from Supernovae Double laser extraction with the CHARISMA Instrument (Argonne National Laboratory)

  22. Lessons from X-grains • Although previously hypothesized, a new type of nucleosynthesis was recognized in nature • The neutron burst required is a natural consequence of Type II supernova explosions • X-grains (at least these ones) must come from Type II, not Type Ia supernovae, as such a burst does not occur in SN Ia • Since n-burst signature comes from an O-rich zone, this material must have mixed with C-rich matter prior to SiC condensation

  23. Conclusions • Stardusts recovered from pristine Carbonaceous Meteorites carry the nucleosynthesis signature of their parent stars. • Different populations have been discovered so far (SiC, graphite, diamonds, silicates, corundum, spinel, hibonite) from Red Giants, AGBs, Novae, Supernovae. • Isotopic analysis in the laboratory of major elements and of trace elements are unique opportunities to test stellar evolution and nucleosynthesis theories for stars of different masses and metallicities. • For light isotopes like Si, Mg, Ca, Ti stardusts are useful tools to infer the chemical evolution of the Galactic thin disk.

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