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A probable stellar solution to the cosmological lithium discrepancy

Abstract

The measurement of the cosmic microwave background has strongly constrained the cosmological parameters of the Universe1. When the measured density of baryons (ordinary matter) is combined with standard Big Bang nucleosynthesis calculations2,3, the amounts of hydrogen, helium and lithium produced shortly after the Big Bang can be predicted with unprecedented precision1,4. The predicted primordial lithium abundance is a factor of two to three higher than the value measured in the atmospheres of old stars5,6. With estimated errors of 10 to 25%, this cosmological lithium discrepancy seriously challenges our understanding of stellar physics, Big Bang nucleosynthesis or both. Certain modifications to nucleosynthesis have been proposed7, but found experimentally not to be viable8. Diffusion theory, however, predicts atmospheric abundances of stars to vary with time9, which offers a possible explanation of the discrepancy. Here we report spectroscopic observations of stars in the metal-poor globular cluster NGC 6397 that reveal trends of atmospheric abundance with evolutionary stage for various elements. These element-specific trends are reproduced by stellar-evolution models with diffusion and turbulent mixing10. We thus conclude that diffusion is predominantly responsible for the low apparent stellar lithium abundance in the atmospheres of old stars by transporting the lithium deep into the star.

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Figure 1: Trends of iron and lithium as a function of the effective temperatures of the observed stars compared to the model predictions.

References

  1. 1

    Spergel, D. N. et al. Wilkinson Microwave Anisotropy Probe (WMAP) three year results: implications for cosmology. Astrophys. J. (submitted); preprint at http://arxiv.org/abs/astro-ph/0603449 (2006)

  2. 2

    Wagoner, R. V., Fowler, W. A. & Hoyle, F. On the synthesis of elements at very high temperatures. Astrophys. J. 148, 3–49 (1967)

    ADS  CAS  Article  Google Scholar 

  3. 3

    Burles, S., Nollett, K. M. & Turner, M. S. Big bang nucleosynthesis predictions for precision cosmology. Astrophys. J. 552, L1–L5 (2001)

    ADS  CAS  Article  Google Scholar 

  4. 4

    Cyburt, R. H., Fields, B. D. & Olive, K. A. Primordial nucleosynthesis in light of WMAP. Phys. Lett. B 567, 227–234 (2003)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Spite, M. & Spite, F. Lithium abundance at the formation of the galaxy. Nature 297, 483–485 (1982)

    ADS  CAS  Article  Google Scholar 

  6. 6

    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 

  7. 7

    Coc, A., Vangioni-Flam, E., Descouvemont, P., Adahchour, A. & Angulo, C. Updated big bang nucleosynthesis compared with Wilkinson Microwave Anisotropy Probe observations and the abundance of light elements. Astrophys. J. 600, 544–552 (2004)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Angulo, C. et al. The 7Be(d,p)2α cross section at big bang energies and the primordial 7Li abundance. Astrophys. J. 630, L105–L108 (2005)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Aller, L. H. & Chapman, S. Diffusion in the sun. Astrophys. J. 132, 461–472 (1960)

    ADS  Article  Google Scholar 

  10. 10

    Richard, O., Michaud, G. & Richer, J. Implications of WMAP observations on Li abundance and stellar evolution models. Astrophys. J. 619, 538–548 (2005)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Michaud, G., Fontaine, G. & Beaudet, G. The lithium abundance: constraints on stellar evolution. Astrophys. J. 282, 206–213 (1984)

    ADS  CAS  Article  Google Scholar 

  12. 12

    Guzik, J. A. & Cox, A. N. On the sensitivity of high-degree p-mode frequencies to the solar convection zone helium abundance. Astrophys. J. 386, 729–733 (1992)

    ADS  CAS  Article  Google Scholar 

  13. 13

    Richer, J., Michaud, G. & Turcotte, S. The evolution of AMFM stars, abundance anomalies, and turbulent transport. Astrophys. J. 529, 338–356 (2000)

    ADS  CAS  Article  Google Scholar 

  14. 14

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

    ADS  CAS  Article  Google Scholar 

  15. 15

    King, J. R., Stephens, A., Boesgaard, A. M. & Deliyannis, C. Keck HIRES spectroscopy of M92 subgiants—surprising abundances near the turnoff. Astron. J. 115, 666–684 (1998)

    ADS  CAS  Article  Google Scholar 

  16. 16

    Gratton, R. G. et al. The O-Na and Mg-Al anticorrelations in turn-off and early subgiants in globular clusters. Astron. Astrophys. 369, 87–98 (2001)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Cohen, J. G. & Meléndez, J. Abundances in a large sample of stars in M3 and M13. Astron. J. 129, 303–329 (2005)

    ADS  CAS  Article  Google Scholar 

  18. 18

    Fuhrmann, K., Axer, M. & Gehren, T. Balmer lines in cool dwarf stars. I. Basic influence of atmospheric models. Astron. Astrophys. 271, 451–462 (1993)

    ADS  CAS  Google Scholar 

  19. 19

    Barklem, P. S., Piskunov, N. & O'Mara, B. J. Self-broadening in Balmer line wing formation in stellar atmospheres. Astron. Astrophys. 363, 1091–1105 (2000)

    ADS  CAS  Google Scholar 

  20. 20

    Korn, A. J., Shi, J. & Gehren, T. Kinetic equilibrium of iron in the atmospheres of cool stars. III. The ionization equilibrium of selected reference stars. Astron. Astrophys. 407, 691–703 (2003)

    ADS  CAS  Article  Google Scholar 

  21. 21

    Stein, R. F. & Nordlund, Å. Simulations of solar granulation. I. General properties. Astrophys. J. 499, 914–933 (1998)

    ADS  Article  Google Scholar 

  22. 22

    Strömgren, B., Gustafsson, B. & Olsen, E. H. Evidence of helium abundance differences between the Hyades stars and field stars, and between Hyades stars and Coma cluster stars. Astron. Soc. Pacif. 94, 5–15 (1982)

    ADS  Article  Google Scholar 

  23. 23

    Charbonnel, C. & Primas, F. The lithium content of the galactic halo stars. Astron. Astrophys. 442, 961–992 (2005)

    ADS  CAS  Article  Google Scholar 

  24. 24

    Piau, L. et al. From first stars to the Spite plateau: a possible reconciliation of halo stars observations with predictions from big bang nucleosynthesis. Astrophys. J. (submitted); preprint at http://arxiv.org/abs/astro-ph/0603553 (2006)

  25. 25

    VandenBerg, D. A., Richard, O., Michaud, G. & Richer, J. Models of metal-poor stars with gravitational settling and radiative accelerations. II. The age of the oldest stars. Astrophys. J. 571, 487–500 (2002)

    ADS  Article  Google Scholar 

  26. 26

    Charbonnel, C. & Talon, S. Influence of gravity waves on the internal rotation and Li abundance of solar-type stars. Science 309, 2189–2191 (2005)

    ADS  CAS  Article  PubMed  Google Scholar 

  27. 27

    Frebel, A. et al. Nucleosynthetic signatures of the first stars. Nature 434, 871–873 (2005)

    ADS  CAS  Article  Google Scholar 

  28. 28

    Alonso, A., Arribas, S. & Martinez-Roger, C. The effective temperature scale of giant stars (F0–K5). II. Empirical calibration of Teff versus colours and [Fe/H]. Astron. Astrophys. Suppl. 140, 261–277 (1999)

    ADS  CAS  Article  Google Scholar 

  29. 29

    Barklem, P. S., Belyaev, A. K. & Asplund, M. Inelastic H + Li and H- + Li+ collisions and non-LTE Li I line formation in stellar atmospheres. Astron. Astrophys. 409, L1–L4 (2003)

    ADS  CAS  Article  Google Scholar 

  30. 30

    Charbonnel, C. A consistent explanation for 12C/13C, 7Li and 3He anomalies in red giant stars. Astrophys. J. 453, L41–L44 (1995)

    ADS  CAS  Article  Google Scholar 

Download references

Acknowledgements

A.J.K. acknowledges a research fellowship by the Leopoldina Foundation, Germany. O.R. thanks the Centre Informatique National de l'Enseignement Supérieur (CINES) and the Réseau Québécois de Calcul de Haute Performance (RQCHP) for providing the computational resources required for this work. F.G. acknowledges financial support from the Instrument Center for Danish Astrophysics (IDA). L.M. acknowledges support through the Presidium RAS Programme 'Origin and evolution of stars and the Galaxy'. The Uppsala group of authors acknowledges support from the Swedish Research Council. We thank A. Alonso and I. Ramirez for providing colour–temperature relations specific to this project.

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Correspondence to A. J. Korn.

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Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Figures 1 and 2 and Supplementary Table 1

Supplementary Figure 1 shows the loci of the observed stars in the observational and physical parameter space. Supplementary Figure 2 displays trends of calcium and titanium as a function of the effective temperatures of the observed star. Supplementary Table 1 compares spectroscopic and photometric effective temperatures of the four groups of stars. (PDF 148 kb)

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Korn, A., Grundahl, F., Richard, O. et al. A probable stellar solution to the cosmological lithium discrepancy. Nature 442, 657–659 (2006). https://doi.org/10.1038/nature05011

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