Identification of the solar emission lines near 12 microns

The emission lines in the far-infrared solar spectrum discussed here were reported by Murcray et al. (1981) and Brault and Noyes (1983). The two strong emission lines, at 12.32 and 12.22 microns, appear at disk center and brighten greatly toward the limb. More than 40 additional limb-brightened lines appear near the limb, and most of these are too weak to be seen at disk center. These lines are identified here as transitions between Rydberg states of neutral magnesium and aluminum.