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Heavy element synthesis in the oldest stars and the early Universe

Nature volume 440, pages 1151–1156 (2006)Cite this article

Abstract

The first stars in the Universe were probably quite different from those born today. Composed almost entirely of hydrogen and helium (plus a tiny trace of lithium), they lacked the heavier elements that determine the formation and evolution of younger stars. Although we cannot observe the very first stars — they died long ago in supernovae explosions — they created heavy elements that were incorporated into the next generation. Here we describe how observations of heavy elements in the oldest surviving stars in our Galaxy's halo help us understand the nature of the first stars — those responsible for the chemical enrichment of our Galaxy and Universe.

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Figure 1: Abundance comparisons between measured and predicted isotopic abundances.
Figure 2: Spectra featuring three n-capture lines in the Sun and two contrasting low-metallicity stars.
Figure 3: Elemental ratios for galactic halo and disk stars.
Figure 4: Abundances in the very metal-poor halo star CS22892–052.
Figure 5: Elemental abundance patterns in galactic halo stars.
Figure 6: Relative abundances of the elemental ratio [Ge/H] as a function of metallicity (Fe).
Figure 7: Abundance trends for the ratio La/Eu in galactic stars.

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Acknowledgements

We dedicate this paper to the memory of Al Cameron, who was a giant in this field and who taught us much about nuclear astrophysics and life. We thank our colleagues for discussions and insights, and Jason Collier and Randi Worhatch for their help with the paper. We also acknowledge support from the National Science Foundation and the Space Telescope Science Institute.

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  1. Department of Physics and Astronomy, University of Oklahoma, Norman, 73019, Oklahoma, USA

    John J. Cowan

  2. Department of Astronomy and McDonald Observatory, University of Texas, Austin, 78712, Texas, USA

    Christopher Sneden

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Cowan, J., Sneden, C. Heavy element synthesis in the oldest stars and the early Universe. Nature 440, 1151–1156 (2006). https://doi.org/10.1038/nature04807

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