The Effect of the Absorption Lines on the Temperature Distribution of the Solar Atmosphere.

In this paper the influence of the absorption lines on the temperature distribution of a stellar at- mosphere is reconsidered, using the new methods in the theory of radiative equilibrium. The analysis is carried out by solving simultaneously the appropriate equations of transfer for the continuous and the line spectra, under the condition of a constant net flux and on the assumption that the probability of occurrence of an absorption line at a frequency ~` is governed by a distribution function w2(v). When w2(v) is independent of frequency, several cases are investigated according to whether the lines arise in absorption and/or scattering. When w2(v) is not constant throughout the spectrum, only the case of pure local thermodynamical equilibrium is considered. For the various cases considered, numerical models are computed in the first two approximations. These models are characterized by an emergent flux in the lines of the same order of magnitude as that observed in the solar spectrum. From the discussion of the different models, a value for the boundary temperature of the sun near 4f~)ØO K is derived. Further, it is shown that the darkening in integrated light of the solar disk is accounted for in terms of the com- bined darkening in the lines and in the continuum of one of the models considered. Finally, some remarks on the phenomenon of monochromatic darkening are also made