Lithium abundances and rotational behavior for bright giant stars

Abstract

Aims. We study the links possibly existing between the lithium content of bright giant stars and their rotational velocity. Methods. We performed a spectral analysis of 145 bright giant stars (luminosity class II) spanning the spectral range from F3 to K5. All these stars have homogeneous rotational velocity measurements available in the literature. Results. For all the stars of the sample, we provide consistent lithium abundances (ALi), effective temperatures (Teff), projected rotational velocity (v sin i), mean metallicity ([Fe/H]), stellar mass, and an indication of the stellar multiplicity. The gradual decrease in lithium abundance with Teff is confirmed for bright giant stars, and it points to a dilution factor that is at least as significant as in giant stars. From the F to K spectral types, the ALi spans at least three orders of magnitude, reflecting the effects of stellar mass and evolution on dilution. Conclusions. We find that the behavior of ALi as a function of v sin i in bright giant stars presents the same trend as is observed in giants and subgiants: stars with high ALi are moderate or fast rotators, while stars with low A Li show a wide range of v sin i values. © ESO 2006.