Letter | Published:

Imprints of fast-rotating massive stars in the Galactic Bulge

Nature volume 472, pages 454457 (28 April 2011) | Download Citation

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  • A Corrigendum to this article was published on 08 June 2011

This article has been updated

Abstract

The first stars that formed after the Big Bang were probably massive1, and they provided the Universe with the first elements heavier than helium (‘metals’), which were incorporated into low-mass stars that have survived to the present2,3. Eight stars in the oldest globular cluster in the Galaxy, NGC 6522, were found to have surface abundances consistent with the gas from which they formed being enriched by massive stars4 (that is, with higher α-element/Fe and Eu/Fe ratios than those of the Sun). However, the same stars have anomalously high abundances of Ba and La with respect to Fe4, which usually arises through nucleosynthesis in low-mass stars5 (via the slow-neutron-capture process, or s-process). Recent theory suggests that metal-poor fast-rotating massive stars are able to boost the s-process yields by up to four orders of magnitude6, which might provide a solution to this contradiction. Here we report a reanalysis of the earlier spectra, which reveals that Y and Sr are also overabundant with respect to Fe, showing a large scatter similar to that observed in extremely metal-poor stars7, whereas C abundances are not enhanced. This pattern is best explained as originating in metal-poor fast-rotating massive stars, which might point to a common property of the first stellar generations and even of the ‘first stars’.

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Change history

  • 08 June 2011

    Errors in Table 1 have been corrected in the HTML and PDF and described in the accompanying Corrigendum.

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Acknowledgements

C.C., U.F., G.M., T.D. and A.M. acknowledge support from the Swiss National Science Foundation (SNSF). M.P. acknowledges support from an Ambizione grant from the SNSF, and from NSF grant PHY 02-16783 (Joint Institute for Nuclear Astrophysics, JINA). B.B. acknowledges support from FAPESP and CNPq (Brazil). C.C. and T.D. acknowledge partial support from ESF-EuroGENESIS. R.H. acknowledges support from the World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan. This work is based on observations collected at the European Southern Observatory (ESO).

Author information

Affiliations

  1. Astrophysikalisches Institut Potsdam, An der Sternwarte 16, Potsdam, 14482, Germany

    • Cristina Chiappini
  2. Geneva Observatory, University of Geneva, 51 Ch. des Maillettes, Sauverny, 1290, Switzerland

    • Cristina Chiappini
    • , Georges Meynet
    • , Thibaut Decressin
    •  & André Maeder
  3. Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, Trieste, 34143, Italy

    • Cristina Chiappini
  4. Department of Physics, University of Basel, Klingelbergstrasse 82, Basel, 4056, Switzerland

    • Urs Frischknecht
    •  & Marco Pignatari
  5. Astrophysics Group, Keele University, ST5 5BG, Keele, England

    • Urs Frischknecht
    •  & Raphael Hirschi
  6. IPMU, University of Tokyo, Kashiwa, Chiba, 277-8582, Japan

    • Raphael Hirschi
  7. University of São Paulo, IAG, Rua do Matão 1226, Cidade Universitaria, 05508-900, São Paulo, Brazil

    • Beatriz Barbuy

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Contributions

C.C. led the analysis and the write-up of the paper. U.F., R.H., G.M. and A.M. computed the new stellar evolution models. B.B. measured the chemical abundances. T.D. and M. P. contributed to the analysis. All authors contributed to the analysis and text writing.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Cristina Chiappini.

Supplementary information

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    Supplementary Information

    This file contains Supplementary Text, additional references and Supplementary Figures 1-4 with legends.

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https://doi.org/10.1038/nature10000

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