Abstract

Light elements can give us important information about the mixing processes inside stellar interiors. However, their depletion mechanisms are not completely understood yet. A wide spread in Li and Be abundances has been observed in clusters like M67 or NGC3960 as well as in field solar type stars but it cannot be explained with standard models. In this work we present new determinations of lithium abundances for 326 main sequence stars with and without planets in the Teff range 5600-5900 K, observed inside HARPS-GTO samples or with other high-resolution spectrographs. We confirm significant differences in the Li distribution of solar twins (solar Teff ± 80 K, solar log g ± 0.2 and -0.2 < [Fe/H] < 0.2): the full sample of planet host stars (22) shows Li average values lower than ""single"" stars with no detected planets (60). If we focus on subsamples with narrower ranges in metallicity and age, we observe indications of a similar result though it is not so clear for some of the subsamples. Moreover, we find indications that the amount of depletion of Li in planet-host solar-type stars is higher when the planets are more massive than Jupiter. We suggest that the presence of planets might cause additional rotationally induced mixing in the external layers of planet host stars and thus an extra Li depletion.

Presentation

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