A study of the emission lines of prominences

A method for studying the emission lines of solar prominences is described in which the observed profiles of closely spaced triplet emission lines in a prominence are used to determine the source function and optical depth for various distances from the center of such a line. Results are summarized for an application of the method to the green triplet lines of Mg and the Balmer lines H10, H11, and H12 in a quiescent prominence. The results reported show that: (1) the source function is not constant within a line; (2) the source function increased by 35% from the center of a hydrogen line to its periphery but remained relatively constant for the Mg lines; and (3) the optical depth of the prominence along the line of sight was 1.229 at the center of the H12 line and 0.1291 at the center of the Mg line at 5167.3216 A.