Spectroscopic determination of atmospheric parameters of solar-type stars: Description of the method and application to the Sun

A computer program has been developed for determining the fundamental model atmosphere parameters (T-eff, log g, nu(t), [Fe/H]) of solar-type stars, which is based on the equivalent widths for a well-chosen set of Fe I and Fe II lines. The basic principle of this method is to find the solution in the (T-eff, log g, nu(t)) space, which minimizes the sum of the dispersion of the Fe I abundances and the square of the Fe I-Fe II abundance difference. An application of this code to the observed solar equivalent widths turned out to yield satisfactory results, which are more or less consistent with the actual parameters of the Sun. The numerical performance of this approach as well as the errors involved in the resulting solutions are discussed.