Temperature variations in the solar photosphere

We made detailed LTE calculations of the sensitivities of some Fraunhofer lines to local variations of the effective temperature of the Sun, taking also into account the effects of local variations of the microturbulence. The temperature sensitivities we got show a clear dependence upon the mean optical depth at which lines originate and upon the binding energy of the lower level involved in the transition.A list of some selected lines is given, in view of possible measurements either of any pole equator-variation of the effective temperature or of such local effects as those connected with the presence of strong non-spot magnetic fields.Arcetri Astrophysical Observatory, Florence, Italy.