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Abstract

The chemically most primitive stars provide constraints on the nature of the first stellar objects that formed in the Universe; elements other than hydrogen, helium and traces of lithium present within these objects were generated by nucleosynthesis in the very first stars. The relative abundances of elements in the surviving primitive stars reflect the masses of the first stars, because the pathways of nucleosynthesis are quite sensitive to stellar masses. Several models1,2,3,4,5 have been suggested to explain the origin of the abundance pattern of the giant star HE0107–5240, which hitherto exhibited the highest deficiency of heavy elements known1,6. Here we report the discovery of HE1327–2326, a subgiant or main-sequence star with an iron abundance about a factor of two lower than that of HE0107–5240. Both stars show extreme overabundances of carbon and nitrogen with respect to iron, suggesting a similar origin of the abundance patterns. The unexpectedly low Li and high Sr abundances of HE1327–2326, however, challenge existing theoretical understanding: no model predicts the high Sr abundance or provides a Li depletion mechanism consistent with data available for the most metal-poor stars.

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References

  1. 1.

    et al. A stellar relic from the early Milky Way. Nature 419, 904–906 (2002)

  2. 2.

    , & Excavation of the first stars. Astrophys. J. 568, L57–L60 (2003)

  3. 3.

    & First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star. Nature 422, 871–873 (2003)

  4. 4.

    , & On the origin of HE 0107–5240, the most iron-deficient star presently known. Astrophys. J. 594, L123–L126 (2003)

  5. 5.

    , , , & Is HE 0107–5240 a primordial star? The characteristics of extremely metal-poor carbon-rich stars. Astrophys. J. 611, 476–493 (2004)

  6. 6.

    et al. HE 0107–5240, a chemically ancient star. I. A detailed abundance analysis. Astrophys. J. 603, 708–728 (2004)

  7. 7.

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

  8. 8.

    et al. High dispersion spectrograph (HDS) for the Subaru telescope. Publ. Astron. Soc. Jpn 54, 855–864 (2002)

  9. 9.

    & The discovery and analysis of very metal-poor stars in the galaxy. Annu. Rev. Astron. Astrophys. (in the press)

  10. 10.

    , , , & Updated big bang nucleosynthesis compared with Wilkinson microwave anisotropy probe observations and the abundance of light elements. Astrophys. J. 600, 544–552 (2004)

  11. 11.

    , & The Spite lithium plateau: ultrathin but postprimordial. Astrophys. J. 523, 654–677 (1999)

  12. 12.

    , , , & Rapid rotation of ultra-Li-depleted halo stars and their association with blue stragglers. Astrophys. J. 571, 501–511 (2002)

  13. 13.

    , , & Halo star lithium depletion. Astrophys. J. 527, 180–198 (1999)

  14. 14.

    , & Models of metal-poor stars with gravitational settling and radiative accelerations. III. Metallicity dependence. Astrophys. J. 580, 1100–1117 (2002)

  15. 15.

    , , , & Detection of lead in the carbon-rich, very metal-poor star LP 625–44: A strong constraint on s-process nucleosynthesis at low metallicity. Astrophys. J. 536, L97–L100 (2000)

  16. 16.

    et al. Galactic evolution of Sr, Y, and Zr. A multiplicity of nucleosynthetic processes. Astrophys. J. 601, 864–884 (2004)

  17. 17.

    et al. The Hamburg/ESO R-process enhanced star survey (HERES). I. Project description, and discovery of two stars with strong enhancements of neutron-capture elements. Astron. Astrophys. 428, 1027–1037 (2004)

  18. 18.

    , & Pair instability supernovae, gravity waves, and gamma-ray transients. Astrophys. J. 550, 372–382 (2001)

  19. 19.

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

  20. 20.

    , , & Extremely metal-poor stars. III. The Li-depleted main-sequence turnoff dwarfs. Astrophys. J. 485, 370–379 (1997)

  21. 21.

    , , , & Estimation of stellar metal abundance. II. A recalibration of the Ca II K technique, and the autocorrelation function method. Astron. J. 117, 981–1009 (1999)

  22. 22.

    New light on stellar abundances analyses: departures from LTE and homogeneity. Annu. Rev. Astron. Astrophys. (in the press)

  23. 23.

    , & On the oxygen abundance of HE 0107–5240. Astrophys. J. 612, L61–L63 (2004)

  24. 24.

    , & The empirical scale of temperatures of the low main sequence (F0V–K5V). Astron. Astrophys. 313, 873–890 (1996)

  25. 25.

    in New Trends in Theoretical and Observational Cosmology (eds Sato, K. & Shiromizu, T.) 235–244 (Universal Academy, Tokyo, 2002)

  26. 26.

    , et al. 2MASS All-Sky Catalog of Point Sources (California Institute of Technology, Pasadena, 2003);

  27. 27.

    et al. The southern proper motion program. III. A near-complete catalog to V = 17.5. Astron. J. 127, 3060–3071 (2004)

  28. 28.

    , , & The Y2 isochrones for alpha-element enhanced mixtures. Astrophys. J. Suppl. 143, 499–511 (2002)

  29. 29.

    ATLAS9 Stellar Atmosphere Programs and 2 km/s Grid CD-ROM 13 (Smithsonian Astrophysical Observatory, Cambridge, 1993);

  30. 30.

    Asplund, M., Grevesse, N. & Sauval, A. J. in Cosmic Abundances As Records Of Stellar Evolution And Nucleosynthesis (eds Bash, F. N. & Barnes, T. G.) ASP Conf. Ser. (in the press); preprint at (2004).

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Acknowledgements

We thank A. Steinhauer and C. Thom for obtaining additional observations, N. Iwamoto, K. Maeda, T. Suda, N. Tominaga and H. Umeda for valuable discussions and L. Wisotzki and D. Reimers for leading the HES. This work was supported by the Astronomical Society of Australia (A.F.), Australian Research Council (M.A., A.F., J.E.N.), Ministry of Education, Culture, Sports, Science and Technology in Japan and JSPS (all Japanese co-authors), Deutsche Forschungsgemeinschaft (N.C.), Swedish Research Council (P.S.B., K.E.), US National Science Foundation (T.C.B.) and JINA (T.C.B., N.C., A.F., J.E.N.). This work is based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

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Affiliations

  1. Research School of Astronomy & Astrophysics, The Australian National University, Cotter Road, Weston Creek, Australian Capital Territory 2611, Australia

    • Anna Frebel
    • , Martin Asplund
    •  & John E. Norris
  2. National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan

    • Wako Aoki
    • , Norbert Christlieb
    • , Hiroyasu Ando
    • , Satoshi Honda
    •  & Toshitaka Kajino
  3. Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany

    • Norbert Christlieb
    •  & Cora Fechner
  4. Department of Physics and Space Sciences, Uppsala Astronomical Observatory, Box 515, SE-751 20 Uppsala, Sweden

    • Paul S. Barklem
    •  & Kjell Eriksson
  5. Department of Physics and Astronomy, and Joint Institute for Nuclear Astrophysics (JINA), Michigan State University, East Lansing, Michigan 48824, USA

    • Timothy C. Beers
  6. Department of Physics, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan

    • Masayuki Y. Fujimoto
  7. Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015, Japan

    • Takeo Minezaki
    •  & Yuzuru Yoshii
  8. Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan

    • Ken'ichi Nomoto
  9. Department of Physics and Astronomy, Open University, Walton Hall, Milton Keynes MK7 6AA, UK

    • Sean G. Ryan
    •  & Stelios Tsangarides
  10. Liberal Arts Education Center, Tokai University, 1117 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan

    • Masahide Takada-Hidai

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The authors declare that they have no competing financial interests.

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Correspondence to Anna Frebel.

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https://doi.org/10.1038/nature03455

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