HEIGHT OF FORMATION OF SOLAR PHOTOSPHERIC SPECTRAL-LINES

The dependence of the line depression contribution functions of spectral lines on the relevant line parameters in the solar photosphere is investigated. It is shown how the formation height range varies as function of excitation and ionization potential, line strength, central wavelength and wavelength offset. Furthermore it is shown that the type of contribution function used provides reliable information on the depth where a given line - or part of the line - is sensitive to atmospheric field quantities like, for example, the bulk velocity.