SIMBAD references

We have computed a grid of synthetic spectra in the wavelength range λλ 4600-5600Å using revised model atmospheres, for a range of atmospheric parameters and values of [α-elements/Fe]=0.0 and +0.4. The Lick indices Fe5270, Fe5335, Mgb and Mg₂ are measured on the grid spectra for FWHM=2 to 8.3Å. Relations between the indices Fe5270, Fe5335 and Mg₂ and the stellar parameters effective temperature T_eff, log g, [Fe/H] and [α/Fe], valid in the range 4000≤T_eff≤7000K, are presented. These fitting functions are given for FWHM=3.5 and 8.3Å. The indices were also measured for a list of 97 reference stars with well-known stellar parameters observed at ESO and OHP, and these are compared to the computed indices. Finally, a comparison of the indices measured on the observed spectra and those derived from the fitting functions based on synthetic spectra is presented.