摘要：Context.Mixing-length theory is used to treat stellar convection. As a simulation in one-dimensional stellar atmospheres models, the mixing-length parameterαis calibrated from the Sun and then applied to other stars. However, there is no strong evidence to suggest thatαshould be the same for stars of different evolutionary stages.Aims.We evaluate the impact of theαvalue on the metallicity of different types of stars and investigate the correlation between the metallicity discrepancy (Δ[Fe∕H]) and stellar parameters (Teff, logg).Methods.We selected ten well-studied field stars and one open cluster of nine members for which high-resolution and high signal-to-noise spectra are available. The model atmospheres were calculated with the code MAFAGS-OS. We derived iron abundances from Fe Iand Fe IIlines both under local thermodynamic equilibrium and non-LTE conditions using a spectrum synthesis method. After deriving [Fe/H] for each line, we calculated Δ[Fe∕H] with two differentαvalues, fixed solar-calibratedα, andαobtained for each star individually. Finally, we investigated the correlation between Δ[Fe∕H] caused by revisedαwith stellar parameters.Results.For FGK dwarf stars, the Δ[Fe∕H] caused by theαcorrection is less than 0.02 dex, while for turn-off and giant stars, the Δ[Fe∕H] values are no more than 0.03 dex, which are lower than typical uncertainties in metallicity. For main-sequence stars, Δ[Fe∕H] versusTeffand Δ[Fe∕H] versus loggare well fit by linear relations.
关键词：Key wordsenstars: atmospheresstars: abundancesstars: fundamental parametersconvectionline: profiles
