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Mixing Along the Red Giant Branch in Metal-Poor Field Stars

  • E. Carretta
  • R. G. Gratton
  • C. Sneden
  • A. Bragaglia
Part of the Astrophysics and Space Science Library book series (ASSL, volume 255)

Abstract

Stellar models predict that as a small mass star evolves up the RGB, the outer convective envelope expands inward and penetrates into the CN-cycle processed interior regions (first dredge-up). Approximately, the outer 50% of the star by mass is involved in this mixing that brings to the surface mainly 13C and 14N, while the primordial 12C and fragile, light elements like Li, Be, and B are transported from the surface to the interior. Results for old disk field giants (Shetrone et al. 1993) and metal-poor stars (Sneden et al. 1986) show that the first dredge-up occurs at the predicted luminosities; however, mixing in bright giants is much more extreme than predicted by evolutionary models

Keywords

Globular Cluster Carbon Isotope Ratio Convective Envelope Field Star Globular Cluster Star 
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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References

  1. 1.
    Anthony-Twarog, B..1., Twarog, B.A. (1994) Reddening estimation for halo red giants using uvby photometry, Astron. J. 107, 1577ADSCrossRefGoogle Scholar
  2. 2.
    . Carretta, E., Gratton, R..G., Sneden, C. (1999), submitted to Astron. Astrophys Google Scholar
  3. 3.
    Castelli, F., Gratton, R.G., Kurucz, R.L. (1997), Notes on the convection in the ATLAS9 model atmospheres, Astron. Astrophys 318, 841ADSGoogle Scholar
  4. 4.
    Charbonnel, C. (1994), Clues for non-standard mixing on the red giant branch from C-12/C-13 and C-12/N-14 ratios in evolved star, Astron. Astrophys 282, 811ADSGoogle Scholar
  5. 5.
    Charbonnel, C. (1995) A Consistent Explanation for 12C/ 13C, 7Li and 3He Anomalies in Red Giant Stars Ap. J. 453, L41ADSCrossRefGoogle Scholar
  6. 6.
    Clementini, G., Gratton, R.G., Carretta, E., Sneden, C. (1998) Homogeneous photometry and metal abundances for a large sample of Hipparcos metal-poor stars, Mon. Not. R. Astr. Soc 302, 22ADSCrossRefGoogle Scholar
  7. 7.
    Gratton, R..G., Carretta, E., Castelli, F. (1997) Abundances of light elements in metal-poor stars. I. Atmospheric parameters and a new Teff scale, Astron. Astrophys. 314, 191ADSGoogle Scholar
  8. 8.
    Gratton, R.G., Gustafsson, B., Carretta, E., Eriksson, K. (1999) Abundances of light elements in metal-poor stars. II. Non-LTE abundance corrections Astron. Astrophys, 350, 955ADSGoogle Scholar
  9. Gratton, R.G., Sneden, C., Carretta, E., Bragaglia, A. 2000, Astron. Astrophys., inGoogle Scholar
  10. 10.
    Kraft, R.P. (1994) Abundance differences among globular-cluster giants: Primordial versus evolutionary scenarios, Pub. Astr. Soc. Pacific 106, 553ADSCrossRefGoogle Scholar
  11. 11.
    Kurucz, R.L. (1995), CD-ROM 13Google Scholar
  12. 12.
    Pilachowski, C.A., Sneden, C., Booth, J. (1993) The abundance of lithium in metal-poor subgiant stars, Ap. J. 407, 699ADSCrossRefGoogle Scholar
  13. 13.
    Schuster, W.J., Nissen, P.E. (1989) ubvy-beta photometry of high-velocity and metal-poor stars. III - Metallicities and ages of the halo star, Astron. Astrophys. 222, 69ADSGoogle Scholar
  14. 14.
    Shetrone, M.D., Sneden, C., Pilachowski, C.A. (1993) Carbon isotope ratios and lithium abundances in old disk giants, Pub. Astr. Soc. Pacific 105, 337ADSCrossRefGoogle Scholar
  15. 15.
    Sneden, C., Pilachowski, C.A., VandenBerg, D.A. (1986) Carbon isotope ratios in field Population II giant star, Ap. J. 311, 826ADSCrossRefGoogle Scholar
  16. 16.
    Sweigart, A.V., Mengel, J.G. (1979) Meridional circulation and CNO anomalies in red giant stars, Ap. J. 229, 624ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2000

Authors and Affiliations

  • E. Carretta
    • 1
  • R. G. Gratton
    • 1
  • C. Sneden
    • 2
  • A. Bragaglia
    • 3
  1. 1.Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5ITALY
  2. 2.Department of Astronomy and McDonald Observatory The University of Texas at AustinUSA
  3. 3.Osservatorio Astronomico di Bologna via Ranzani 1ITALY

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