Analysis of the Center-To Observations of the Sodium D Lines.

Abstract

With observations obtained at the Sacramento Peak Observatory, it is shown that the source functions of the two sodium D lines are identical at any given geometrical depth A preliminary analysis indicates that the scattering may be treated as purely non-coherent in the line cores. The Doppler widths derived from the profiles appear to be consistent with the results of Unno (1959) and Suemoto (1957), who have shown that the random gas motions increase with depth into the solar photosphere. A condition, other than local thermodynamic equilibrium, is sought that will require the source functioois of the two lines to be identical at a given geometrical depth. This condition is that the collisional interchange between the P2/2 and P2/2 levels must be overwhelmingly larger than the spontaneous emissions between the P and S states of the sodium atom.