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Self-regulated hydrodynamical process in halo stars: a possible explanation of the lithium plateau

Published online by Cambridge University Press:  25 May 2016

Sylvie Théado  and
Sylvie Vauclair
Sylvie Théado
Affiliation:
Laboratoire d’Astrophysique, 14 av. Ed. Belin, 31400 Toulouse, France
Sylvie Vauclair
Affiliation:
Laboratoire d’Astrophysique, 14 av. Ed. Belin, 31400 Toulouse, France

Abstract

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It has been known for a long time (Mestel 1953) that the meridional circulation velocity in stars, in the presence of μ-gradients, is the sum of two terms, one due to the classical thermal imbalance (Ω-currents) and the other one due to the induced horizontal μ-gradients (μ-induced currents, or μ-currents in short). In the most general cases, μ-currents are opposite to Ω-currents. Vauclair (1999) has shown that such processes can, in specific cases, lead to a quasi-equilibrium stage in which both the circulation and the helium settling is frozen. Here we present computations of the circulation currents in halo star models, along the whole evolutionary sequences for four stellar masses with a metallicity of [Fe/H] = −2. We show that such a self-regulated process can account for the constancy of the lithium abundances and the small dispersion in the Spite plateau.

Type
6. Stellar Knowledge to and from Light Elements
Information
Symposium - International Astronomical Union , Volume 198: The Light Elements and their Evolution , 2000 , pp. 520 - 522
Copyright
Copyright © Astronomical Society of the Pacific 2000 

References

Bonifacio, P., & Molaro, P. 1997, MNRAS, 285, 847 CrossRefGoogle Scholar
Maeder, A., & Zahn, J.-P. 1998, A&A, 334, 1000 Google Scholar
Mestel, L. 1953, Mon. Not. R. Astron. Soc., 113, 716 CrossRefGoogle Scholar
Molaro, P. 1999, preprint Google Scholar
Richard, O. 1999, , Google Scholar
Spite, M., & Spite, F. 1982, A&A, 115, 357 Google Scholar
Spite, F., Francois, P., Nissen, P.E., & Spite, M. 1996, ApJ, 408, 262 Google Scholar
Vauclair, S. 1999, A&A, 351, 973 Google Scholar
Vauclair, S. 2000, this conference Google Scholar
Von Zeipel, H. 1924, MNRAS, 84, 665 CrossRefGoogle Scholar
Zahn, J.-P. 1992, A&A, 265, 115 Google Scholar