New measurement of the 6Li/7Li isotopic ratio in the extra-solar planet host star HD 82943 and line blending in the Li 6708 Å region

The presence of possible blends in the spectral region of the Li resonance line at 6708 Angstrom in solar-type metal-rich stars is investigated using high resolution and high signal-to-noise spectroscopic observations. Our analysis does not confirm the identification of a weak absorption feature at 6708.025 Angstrom with the low excitation Ti I line proposed by Reddy et al. (2002). Our spectrum synthesis suggests that the unidentified absorption is most probably produced by a high excitation Si I line originally proposed by Muller et al. (1975). Reanalysis of the Li-6/Li-7 isotopic ratio in HD82943 was performed by taking the Si I line into account and using new VLT/UVES spectra of HD82943 with a signal-to-noise ratio close to 1000. We confirm the presence of Li-6 in the star's atmosphere while the updated value for the isotopic ratio is f(Li-6) = 0.05 +/- 0.02.