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In Search of the Early Universe. I. the Oldest Stars

  • P.W. Hodge
Part of the NATO Science Series book series (ASIC, volume 562)

Abstract

The epoch of galaxyformation can be dated in a numberof ways. This lectureexplores the question of how we can date the oldest identifiable stars. It is shown that reliable ages can only be found for stars that belong to star clusters and that it is still not possible to age-date them to an accuracy of better than approximately 2 Gyr. Indirectevidence also comes from the abundances of the elements in old field stars, but these data are not able to produce precise ages, though they do indicate indirectly the great age of certain stars. Only a very few galaxies have so far been age-dated reliably. These include the galaxies that are near enough to obtain accurate main sequence turn-off magnitudes and colors using, especially, the Hubble Space Telescope. The oldest galaxies so studied have ages of 14.5Gyr, but with uncertainties of at least 2 Gyr, which include both observational and theoretical uncertainties.

Keywords

Early Universe Globular Cluster Hubble Space Telescope Star Cluster Large Magellanic Cloud 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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5. References

  1. 1.
    Harris, W. E. (1991) Globular Cluster Systems, ARA&A. 29,543–579.ADSCrossRefGoogle Scholar
  2. 2.
    Wallerstein, G, Greenstein, J. L., Parker, R. Helfer, H. L., and Aller, L. H. (1963), Abundances of Metal-Poor Stars, ApI, 137, 280–301.ADSCrossRefGoogle Scholar
  3. 3.
    McWilliam, A., Preston, G., Sneden, C. and Searle, L. (1995) Spectroscopic Analysis of 33 of the Most Metal Poor Stars, AJ 109, 2757–2799.ADSCrossRefGoogle Scholar
  4. 4.
    McWilliam, A. (1998) Barium Abundances in Extremely Metal-Poor Stars, AJ 115, 640–647.ADSCrossRefGoogle Scholar
  5. 5.
    Hodge, P. W. (1960) Studies of the Large Magellanic Cloud. I., ApJ 131, 351–357.ADSCrossRefGoogle Scholar
  6. 6.
    Flower, P., Geisler, D., Hodge, P. W., Olszewski, E. and Schommer, R. (1983) The Age and Composition of the LMC Red Globular Cluster NGC 2121, ApJ 265, 15–34.ADSCrossRefGoogle Scholar
  7. 7.
    Olsen, K., Hodge, P.W., Mateo, M., Olszewski, E., Schommer, R.Google Scholar
  8. 8.
    Mateo, M. (1998) Dwarf Galaxies of the Local Group, ARAA, 36, 435–460.ADSCrossRefGoogle Scholar
  9. 9.
    Hodge, P.W., Dolphin, A., Smith, T. and Mateo, M. (1999) ApJ, 521, 577–581.ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2001

Authors and Affiliations

  • P.W. Hodge
    • 1
  1. 1.Astronomy DepartmentUniversity of WashingtonSeattleUSA

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