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A stellar relic from the early Milky Way


The chemical composition of the most metal-deficient stars largely reflects the composition of the gas from which they formed. These old stars provide crucial clues to the star formation history and the synthesis of chemical elements in the early Universe. They are the local relics of epochs otherwise observable only at very high redshifts1,2; if totally metal-free (‘population III’) stars could be found, this would allow the direct study of the pristine gas from the Big Bang. Earlier searches for such stars found none with an iron abundance less than 1/10,000 that of the Sun3,4, leading to the suggestion5,6 that low-mass stars could form from clouds above a critical iron abundance. Here we report the discovery of a low-mass star with an iron abundance as low as 1/200,000 of the solar value. This discovery suggests that population III stars could still exist—that is, that the first generation of stars also contained long-lived low-mass objects. The previous failure to find them may be an observational selection effect.

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Figure 1: A portion of the spectrum of HE0107-5240, shown compared to the spectrum of CD-38° 245, the previously most iron-poor giant star known.


  1. * The citation of Fig. 1 was omitted in all print issues, and the citation of Table 1 was omitted in certain print issues.


  1. Norris, J. E., Ryan, S. G. & Beers, T. C. Extremely metal-poor stars. VIII. High-resolution, high signal-to-noise ratio analysis of five stars with [Fe/H] < -3.5. Astrophys. J. 561, 1034–1059 (2001)

    ADS  CAS  Article  Google Scholar 

  2. Cohen, J. G., Christlieb, N., Beers, T. C., Gratton, R. & Carretta, E. Stellar archaeology: A Keck pilot program on extremely metal-poor stars from the Hamburg/ESO survey. I. Stellar parameters. Astron. J. 124, 470–480 (2002)

    ADS  Article  Google Scholar 

  3. Bond, H. E. Where is population III? Astrophys. J. 248, 606–611 (1981)

    ADS  CAS  Article  Google Scholar 

  4. Beers, T. C. in The Third Stromlo Symposium: The Galactic Halo (eds Gibson, B. K., Axelrod, T. S. & Putman, M. E.) Astron. Soc. Pacif. Conf. Ser. 165, 202–212 (1999).

  5. Bromm, V., Ferrara, A., Coppi, P. S. & Larson, R. B. The fragmentation of pre-enriched primordial objects. Mon. Not. R. Astron. Soc. 328, 969–976 (2001)

    ADS  Article  Google Scholar 

  6. Schneider, R., Ferrara, A., Natarajan, P. & Omukai, K. First stars, very massive black holes, and metals. Astrophys. J. 571, 30–39 (2002)

    ADS  CAS  Article  Google Scholar 

  7. Wisotzki, L. et al. The Hamburg/ESO survey for bright QSOs. III. A large flux-limited sample of QSOs. Astron. Astrophys. 358, 77–87 (2000)

    ADS  CAS  Google Scholar 

  8. Christlieb, N. et al. The stellar content of the Hamburg/ESO survey. I. Automated selection of DA white dwarfs. Astron. Astrophys. 366, 898–912 (2001)

    ADS  CAS  Article  Google Scholar 

  9. Yi, S. et al. Towards better age estimates for stellar populations: The Y2 isochrones for solar mixture. Astrophys. J. Suppl. 136, 417–437 (2001)

    ADS  Article  Google Scholar 

  10. Mathis, J. S. & Lamers, H. J. G. L. M. The origin of the extremely metal-poor post-AGB stars. Astron. Astrophys 259, L39–L42 (1992)

    ADS  CAS  Google Scholar 

  11. Van Winckel, H., Waelkens, C. & Waters, L. B. F. M. The extremely iron-deficient “post-AGB” stars and binaries. Astron. Astrophys. 293, L25–L28 (1995)

    ADS  Google Scholar 

  12. Waters, L. B. F. M., Trams, N. R. & Waelkens, C. A scenario for the selective depletion of stellar atmospheres. Astron. Astrophys. 262, L37–L40 (1992)

    ADS  Google Scholar 

  13. Bakker, E. J. et al. The optical spectrum of HR 4049. Astron. Astrophys. 306, 924–934 (1996)

    ADS  CAS  Google Scholar 

  14. Woosley, S. E. & Weaver, T. A. The evolution and explosion of massive stars. II. Explosive hydrodynamics and nucleosynthesis. Astrophys. J. 101, 181–235 (1995)

    ADS  CAS  Article  Google Scholar 

  15. Yoshii, Y. Metal enrichment in the atmospheres of extremely metal-deficient dwarf stars by accretion of interstellar matter. Astron. Astrophys. 97, 280–290 (1981)

    ADS  CAS  Google Scholar 

  16. McClure, R. D. & Woodsworth, A. W. The binary nature of the Barium and CH stars. III. Orbital parameters. Astrophys. J. 352, 709–723 (1990)

    ADS  Article  Google Scholar 

  17. Fujimoto, M. Y., Ikeda, Y. & Iben, I. Jr The origin of extremely metal-poor carbon stars and the search for population III. Astrophys. J. 529, L25–L28 (2000)

    ADS  CAS  Article  Google Scholar 

  18. Schlattl, H., Salaris, M., Cassisi, S. & Weiss, A. The surface carbon and nitrogen abundances in models of ultra metal-poor stars. Astron. Astrophys. (2002) (in the press); also preprint astro-ph/0205326 at 〈

  19. Siess, L., Livio, M. & Lattanzio, J. Structure, evolution, and nucleosynthesis of primordial stars. Astrophys. J. 570, 329–343 (2002)

    ADS  CAS  Article  Google Scholar 

  20. Norris, J., Ryan, S. G. & Beers, T. C. Extremely metal poor stars. The carbon-rich, neutron capture element-poor object CS 22957 - 027. Astrophys. J. 489, L169–L172 (1997)

    ADS  CAS  Article  Google Scholar 

  21. Aoki, W., Norris, J. E., Ryan, S. G., Beers, T. C. & Ando, H. The chemical composition of carbon-rich, very metal poor stars: a new class of mildly carbon rich objects without excess of neutron-capture elements. Astrophys. J. 567, 1166–1182 (2002)

    ADS  CAS  Article  Google Scholar 

  22. Yoshii, Y. & Sabano, Y. Stability of a collapsing pre-Galactic gas cloud. Publ. Astron. Soc. Jpn 31, 505–521 (1979)

    ADS  Google Scholar 

  23. Palla, F., Salpeter, E. E. & Stahler, S. W. Primordial star formation: the role of molecular hydrogen. Astrophys. J. 271, 632–641 (1983)

    ADS  CAS  Article  Google Scholar 

  24. Gass, H., Liebert, J. & Wehrse, R. Spectrum analysis of the extremely metal-poor carbon dwarf star G77-61. Astron. Astrophys. 189, 194–198 (1988)

    ADS  CAS  Google Scholar 

  25. Yoshii, Y. & Saio, H. Initial mass function for zero-metal stars. Astrophys. J. 301, 587–600 (1986)

    ADS  Article  Google Scholar 

  26. Nakamura, F. & Umemura, M. On the initial mass function of population III stars. Astrophys. J. 548, 19–32 (2001)

    ADS  CAS  Article  Google Scholar 

  27. Ostriker, J. P. & Gnedin, N. Y. Reheating of the universe and population III. Astrophys. J. 472, L63–L67 (1996)

    ADS  Article  Google Scholar 

  28. Ryan, S. G., Norris, J. E. & Beers, T. C. The Spite lithium plateau: ultrathin but postprimordial. Astrophys. J. 523, 654–677 (1999)

    ADS  CAS  Article  Google Scholar 

  29. Cayrel, R. et al. Measurement of stellar age from uranium decay. Nature 409, 691–692 (2001)

    ADS  CAS  Article  Google Scholar 

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We thank the European Southern Observatory for providing us with reduced UVES spectra. We are grateful to M. Asplund, B. Edvardsson, J. Lattanzio, J. Norris, N. Piskunov, B. Plez, D. Reimers, S.G. Ryan, L. Siess and L. Wisotzki for their contributions and suggestions. N.C. acknowledges a Marie Curie Fellowship granted by the European Commission, and support from Deutsche Forschungsgemeinschaft. T.C.B. acknowledges grants of the US National Science Foundation, S.R. support from FAPESP and CNPq, and the Uppsala group from the Swedish Research Council.

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Christlieb, N., Bessell, M., Beers, T. et al. A stellar relic from the early Milky Way. Nature 419, 904–906 (2002).

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