Lithium Abundances of F-, G-, and K-Type Stars: Profile-Fitting Analysis of the Li I 6708 Doublet

Abstract

Abstract An extensive profile-fitting analysis was performed for the Li($+$Fe) 6707–6708 Å feature of nearby 160 F–K dwarfs/subgiants (including 27 planet-host stars) in the Galactic disk ($7000 \,\mathrm{K} \gtrsim T_{\mathrm{eff}} \gtrsim 5000 \,\mathrm{K}, -1 \lesssim \mathrm{[Fe/H]} \lesssim +0.4$), in order to establish the photospheric lithium abundances of these stars. The non-LTE effect (though quantitatively insignificant) was taken into account based on our statistical equilibrium calculations, which were carried out on an adequate grid of models. Our results confirmed most of the interesting observational characteristics revealed by recently published studies, such as the bimodal distribution of the Li abundances for stars at $T_{\mathrm{eff}} \gtrsim 6000 \,\mathrm{K}$, the satisfactory agreement of the upper envelope of the $A(\mathrm{Li})$ vs. $\mathrm{[Fe/H]}$ distribution with the theoretical models, the existence of a positive correlation between $A(\mathrm{Li})$ and the stellar mass, and the tendency of lower lithium abundances of planet-host stars (as compared to stars without planets) at the narrow “transition” region of $5900 \,\mathrm{K} \gtrsim T_{\mathrm{eff}} \gtrsim 5800 \,\mathrm{K}$. The solar Li abundance derived from this analysis is 0.92 ($\mathrm{H} = 12.00$), which is by 0.24 dex lower than the widely referenced standard value of 1.16.