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Astron. Astrophys. 352, 117-128 (1999)

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The galactic lithium evolution revisited *

D. Romano 1,2, F. Matteucci 3,1, P. Molaro 2 and P. Bonifacio 2

1 SISSA/ISAS, Via Beirut 2-4, 34014 Trieste, Italy
2 Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, 34131 Trieste, Italy
3 Dipartimento di Astronomia, Università di Trieste, Via G.B. Tiepolo 11, 34131 Trieste, Italy

Received 26 April 1999 / Accepted 5 October 1999


The evolution of the 7Li abundance in the Galaxy has been computed by means of the two-infall model of Galactic chemical evolution. We took into account several stellar 7Li sources: novae, massive AGB stars, C-stars and Type II SNe. In particular, we adopted new theoretical yields for novae. We also took into account the 7Li production from GCRs. In particular, the absolute yields of 7Li, as suggested by a recent reevaluation of the contribution of GCR spallation to the 7Li abundance, have been adopted.

We compared our theoretical predictions for the evolution of 7Li abundance in the solar neighborhood with a new compilation of data, where we identified the population membership of the stars on a kinematical basis. A critical analysis of extant observations revealed a possible extension of the Li plateau towards higher metallicities (up to [Fe/H] [FORMULA] -0.5 or even -0.3) with a steep rise afterwards.

We conclude that 1) the 7Li contribution from novae is required in order to reproduce the shape of the growth of A(Li) versus [Fe/H], 2) the contribution from Type II SNe should be lowered by at least a factor of two, and 3) the 7Li production from GCRs is probably more important than previously estimated, in particular at high metallicities: by taking into account GCR nucleosynthesis we noticeably improved the predictions on the 7Li abundance in the presolar nebula and at the present time as inferred from measures in meteorites and T Tauri stars, respectively. We also predicted a lower limit for the present time 7Li abundance expected in the bulge, a prediction which might be tested by future observations.

Key words: Galaxy: abundances – Galaxy: evolution – Galaxy: solar neighbourhood

* Tables 3 and 4 are only available in electronic form at the CDS via anonymous ftp to: ftp://cdsarc.u-strasbg.fr/pub/cats/J/A+A/351/117 ( or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/352/117

Send offprint requests to: D. Romano (romano@sissa.it)

© European Southern Observatory (ESO) 1999

Online publication: November 23, 1999