We report new statistical equilibrium calculations for Fe I and Fe II in the atmosphere of Late-Type stars. We used atomic models for Fe I and Fe II having respectively 256 and 190 levels, as well as 2117 and 3443 radiative transitions.Photoionization cross-sections are from the Iron Project. These atomic models were used to investigate NLTE (non local themodynamic equilibrium) effects in iron abundances of Late-Type stars with different atmospheric parameters.We found that most Fe I lines in metal-poor stars are formed in conditions far from LTE (local thermodynamic equilibrium). We derived metallicity corrections of about 0.3 dex with respect to LTE values, for the case of stars with [Fe/H] ∼ −3.0. Fe II is found not to be affected by significant NLTE effects. The main NLTE effect invoked in the case of Fe I is overionization by ultraviolet radiation, thus classical ionization equilibrium is far to be satisfied.An important consequence is that surface gravities derived by LTE analysis are in error and should be corrected before final abundances corrections. This apparently solves the observed discrepancy between spectroscopic surface gravities derived by LTE analyses and those derived from Hipparcos parallaxes.A table of NLTE [Fe/H] and log g values for a sample of metal-poor late-type stars is given.

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Abstract. VLT-UVES high resolution spectra of seven turnoff stars in the metal-poor globular cluster NGC 6397 have been obtained. Atmospheric parameters and abundances of several elements (Li, Na, Mg, Ca, Sc, Ti, Cr, Fe, Ni, Zn and Ba) were derived. The mean iron abundance is [Fe/H] = −2.02, with no star-to-star variation. The mean abundances of the alpha-elements (Ca, Ti) and of the iron-peak elements (Sc, Cr, Ni) are consistent with abundances derived for field stars of similar metallicity. Magnesium is also almost solar, consistent with the values found by Idiart & Thévenin (2000) when non-LTE effects (NLTE hereafter) are taken into account. The sodium abundance derived for five stars is essentially solar, but one object (A447) is clearly Na deficient. These results are compatible with the expected abundance range estimated from the stochastic evolutionary halo model of Argast et al. (2000), in which at the epoch of [Fe/H] ∼−2 the interstellar medium is supposed to become well-mixed.

Abstract. New colour distributions have been derived from wide field UBV RI frames for 36 northern bright elliptical galaxies and a few lenticulars. The classical linear representations of colours against log r were derived, with some improvements in the accuracy of the zero point colours and of the gradients. The radial range of significant measurements was enlarged both towards the galaxy center and towards the outskirts of each object. Thus, the "central colours", integrated within a radius of 3 , and the "outermost colours" averaged near the µV = 24 surface brightness could also be obtained. Some typical deviations of colour profiles from linearity are described. Colour-colour relations of interest are presented. Very tight correlations are found between the U − V colour and the Mg2 line-index, measured either at the Galaxian center or at the effective radius.