HEIGHT OF FORMATION OF SOLAR PHOTOSPHERIC SPECTRAL-LINES

The dependence of the line depression contribution functions of spectr al lines on the relevant line parameters in the solar photosphere is i nvestigated. It is shown how the formation height range varies as func tion of excitation and ionization potential, line strength, central wa velength and wavelength offset. Furthermore it is shown that the type of contribution function used provides reliable information on the dep th where a given line - or part of the line - is sensitive to atmosphe ric field quantities like, for example, the bulk velocity.