Comparison of observed (solid black circles) and synthetic spectra for the K-type star HD 11800 (best fit, red line) in the region of the Ca II triplet (the λ∼8498 and λ∼8542 Å Ca II lines are shown). Note that the cores of these lines are not well reproduced. Some metallic lines used to determine the metallicity of the sample stars are indicated (see text). This star belongs to the very young open cluster NGC 743 (see Table 2).