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Li isotopes in metal-poor halo dwarfs: a more and more complicated story

Published online by Cambridge University Press:  23 April 2010

Monique Spite  and
François Spite
Monique Spite
Affiliation:
GEPI, Observatoire de Paris, 92195 Meudon Cedex, CNRS UMR 8111 email: [email protected], [email protected]
François Spite
Affiliation:
GEPI, Observatoire de Paris, 92195 Meudon Cedex, CNRS UMR 8111 email: [email protected], [email protected]
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Abstract

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The nuclei of the lithium isotopes are fragile, easily destroyed, so that, at variance with most of the other elements, they cannot be formed in stars through steady hydrostatic nucleosynthesis.

The 7Li isotope is synthesized during primordial nucleosynthesis in the first minutes after the Big Bang and later by cosmic rays, by novae and in pulsations of AGB stars (possibly also by the ν process). 6Li is mainly formed by cosmic rays. The oldest (most metal-deficient) warm galactic stars should retain the signature of these processes if, (as it had been often expected) lithium is not depleted in these stars. The existence of a “plateau” of the abundance of 7Li (and of its slope) in the warm metal-poor stars is discussed. At very low metallicity ([Fe/H] < −2.7dex) the star to star scatter increases significantly towards low Li abundances. The highest value of the lithium abundance in the early stellar matter of the Galaxy (logϵ(Li) = A(7Li) = 2.2 dex) is much lower than the the value (logϵ(Li) = 2.72) predicted by the standard Big Bang nucleosynthesis, according to the specifications found by the satellite WMAP. After gathering a homogeneous stellar sample, and analysing its behaviour, possible explanations of the disagreement between Big Bang and stellar abundances are discussed (including early astration and diffusion). On the other hand, possibilities of lower productions of 7Li in the standard and/or non-standard Big Bang nucleosyntheses are briefly evoked.

A surprisingly high value (A(6Li)=0.8 dex) of the abundance of the 6Li isotope has been found in a few warm metal-poor stars. Such a high abundance of 6Li independent of the mean metallicity in the early Galaxy cannot be easily explained. But are we really observing 6Li?

Keywords

Stars: abundancesPopulation II – nucleosynthesis – early universe
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S268: Light Elements in the Universe , November 2009 , pp. 201 - 210
Copyright
Copyright © International Astronomical Union 2010

References

Aoki, W., Barklem, P. S., Beers, T. C., Christlieb, N., Inoue, S. et al. 2009, ApJ, 698, 1803CrossRefGoogle Scholar
Alonso, A., Arribas, S., & Martinez-Roger, C. 2009, A&A, 313, 873Google Scholar
Asplund, M., Lambert, D. L., Nissen, P. E., Primas, F., & Smith, V. V. 2006, ApJ, 644, 229CrossRefGoogle Scholar
Asplund, M. & Meléndez, J. 2008, AIP Conf. Proc. FIRST STARS III: First Stars II Conference, Vol. 990, p. 342Google Scholar
Bennett, C. L. et al. 2003, ApJS, 148, 1CrossRefGoogle Scholar
Boesgaard, A. M. 2004, Carnegie Obs. Astrophys. Ser., Vol. 4: Origin and Evolution of the Elements, eds. McWilliam, A. and Rauch, M. (Cambridge: Cambridge Univ. Press)Google Scholar
Boesgaard, A. M., Stephens, A., & Deliyannis, C. P. 2005, ApJ, 63, 398CrossRefGoogle Scholar
Bonifacio, P., Molaro, P., Sivarani, T., Spite, M., Spite, F. et al. 2007, A&A, 462, 851Google Scholar
Bonifacio, P. & Molaro, P. 1997, MNRAS, 285, 847CrossRefGoogle Scholar
Cayrel, R., Spite, M., Spite, F., Vangioni-Flam, E., Cassé, M., & Audouze, J. 1999, A&A, 343, 923Google Scholar
Cayrel, R., Steffen, M., Chand, H., Bonifacio, P., Spite, M., Spite, F. et al. 2007, A&A, 473, L37Google Scholar
Charbonnel, C. & Primas, F. 2005, A&A, 442, 961Google Scholar
Cyburt, R. H., Fields, B. D., & Olive, K. A. 2008, JCAP, 11, 12CrossRefGoogle Scholar
Cyburt, R. H. & Pospelov, M. 2009, arXiv(0906.4373)Google Scholar
Deliyannis, C. P., Demarque, P., & Kawaler, S. D. 1990 ApJS, 73, 21CrossRefGoogle Scholar
Frebel, A., Simon, J. D., Geha, M., & Willman, B. 2010 ApJ, 708, 560CrossRefGoogle Scholar
García Pérez, A. E., Aoki, W., Inoue, S., Ryan, S. G., Suzuki, T. K. et al. 2009, A&A, 504, 213Google Scholar
García Pérez, A. E., Christlieb, N., Ryan, S. G., Beers, T. C. et al. 2008, Physica Scripta, 133, 4036Google Scholar
González Hernández, J., Bonifacio, P., Ludwig, H.-G., Caffau, E., Spite, M., Spite, F. et al. 2008, A&A, 480, 233Google Scholar
Hobbs, L. M. & Thorburn, J. A. 1991, ApJ, 375, 116CrossRefGoogle Scholar
Hosford, A., Ryan, S. G., García Pérez, A. E., Norris, J. E., & Olive, K. A. 2009, A&A, 493, 601Google Scholar
Iocco, F., Mangano, G., Miele, G., Pisanti, O., & Serpico, D. 2009, Phys. Rep., 472, 1CrossRefGoogle Scholar
Komatsu, E., Dunkley, J., Nolta, M. R. et al. 2009, ApJS, 180, 330CrossRefGoogle Scholar
Korn, A. J., Grundahl, F., & Richard, O. 2007, ApJ, 671, 402 (Paper I)CrossRefGoogle Scholar
Meléndez, J., Casagrande, L., Ramírez, I., & Asplund, M. 2010, Proceedings of the IAU symp. 265 “Chemical Abundances in the Universe: Connecting First Stars to Planets”, Cunha, K., Spite, M. & Barbuy, B., eds., Cambridge University Press, p. 71CrossRefGoogle Scholar
Michaud, G., Fontaine, G., & Beaudet, G. 1984, ApJ, 282, 206CrossRefGoogle Scholar
Molaro, P., Primas, F., & Bonifacio, P. 1995, A&A, 348, 211Google Scholar
Nissen Poul, E., Lambert, D. L., Primas, F., & Smith, V. V. 1999, A&A, 295, 47Google Scholar
Piau, L., Beers, T. C., Balsara, D. S., Sivarani, T., Truran, J. W., & Ferguson, J. W. 2006, ApJ, 653, 300CrossRefGoogle Scholar
Pinsonneault, M. H., Deliyannis, C. P., & Demarque, P. 1992, ApJS, 78, 179CrossRefGoogle Scholar
Prantzos, N. 2007, Space Sci. Rev., 130, 27CrossRefGoogle Scholar
Richard, O., Michaud, G., & Richer, J. 2005, ApJ, 619, 538CrossRefGoogle Scholar
Sbordone, L., Bonifacio, P., Caffau, E., Ludwig, H.-G., Behara, N. et al. 2010, Proceedings IAU Symposium No. 265, “Chemical Abundances in the Universe: Connecting First Stars to Planets”, Cunha, K., Spite, M. & Barbuy, B., eds., Cambridge University Press, p. 75Google Scholar
Smith, V. V., Lambert, D. L., & Nissen Poul, E. 1998, ApJ, 408, 262CrossRefGoogle Scholar
Smith, V. V., Lambert, D. L., & Nissen Poul, E. 1998, ApJ, 506, 405CrossRefGoogle Scholar
Spergel, D. N., Bean, R., Doré, O. et al. 2007, ApJS, 170, 377CrossRefGoogle Scholar
Spite, M. & Spite, F. 1982a, Nature, 297, 483CrossRefGoogle Scholar
Spite, F. & Spite, M. 1982b, A&A, 115, 357Google Scholar
Spite, F., Spite, M. & Maillard, J. P. 1984, A&A, 141, 56Google Scholar
Spite, M., Francois, P., Nissen, P. E., & Spite, F. 1996, A&A, 307, 172Google Scholar
Steffen, M., Cayrel, R., Bonifacio, P., Ludwig, H.-G., & Caffau, E. 2010, Proceedings of the IAU symp. 265 “Chemical Abundances in the Universe: Connecting First Stars to Planets”, Cunha, K., Spite, M. & Barbuy, B., eds., Cambridge University Press, p. 23Google Scholar
Talon, S. & Charbonnel, C. 2004, A&A, 418, 1051Google Scholar