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Pop 111 stars

  1. Jul 15, 2005 #1


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    Nucleosynthesis of PopIII Core Collapse Supernovae and the Abundances of Extremely Metal Poor Stars
    Authors: Marco Limongi (INAF-OAR), Alessandro Chieffi (INAF-IAS)
    Comments: 6 pages, 4 figure, Proceedings of the IAU Symp. No. 228 "From Lithium to Uranium: Elemental Tracers of Early Cosmic Evolution", V.Hill, P.Francois & F.Primas eds

    We present a new analysis of the abundances observed in extremely metal poor stars based on both a new generation of theoretical presupernova models and explosions of zero metallicity massive stars and a new abundance analysis of an homogeneous sample of stars having [Fe/H]<-2.5 (Cayrel et al. 2004).
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  3. Jul 15, 2005 #2


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    What mass range for Pop III stars? From that paper
    So not so very massive after all.....
    I wonder, what about the [102 - 104]M range?
    Last edited: Jul 15, 2005
  4. Jul 16, 2005 #3


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    A very speculative paper in my estimation.
  5. Jul 17, 2005 #4
    What does all this really mean?

  6. Jul 18, 2005 #5


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    That our knowledge of the first stars that formed out of the products of the BBN is very sketchy and speculative.

    What we do know is:
    1. There is very early metallicity observed in Lyman alpha forests of quasar spectra, back to z>6.
    2. There was an extended period of re-ionisation of the IGM at an even earlier period prior to z=10.5.
    3. Stars forming out of a primordial gas with little or zero metallicity would be more massive than PopI or PopII stars. This is because metallicity is important to radiate away energy to enable a proto-star to collapse; without it greater gravitational forces are required. Once formed massive stars are expected to have only short lifetimes and they and their demise are expected to have been very bright events. Such bright PopIII stars have not been observed, but it is conceivable that their hyper-novae could be the source of the background GRBs.
    This population could therefore be the source of the re-ionisation and early metallicity, that is if there are enough of them.
    4. There are massive black holes in galactic centres, which may have preceded and been part of the formation of the galaxies themselves.
    5. There seems to be about 10X the amount of mass in galactic halos and clusters than can be directly observed. This may be partially or totally accounted for by BH's of various masses.

    So it is probably correct to say that there are a lot of BHs about. Some of these may be the end product of a ubiquitous population of PopIII stars. The question is of what mass range, and why have these PopIII stars not been observed?

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