Nebular lines | Article about nebular lines by The Free Dictionary
nebular lines[′neb·yə·lər ′līnz]
The spectral lines formed in the glow of bright nebulae; they arise from forbidden atomic transition which can take place because of the very low pressure in the nebula itself.
References in periodicals archive
There were "encouraging results or (I should say) indications," Slipher reported to Lowell, "as there appears to be an appreciable displacement of the nebular lines
toward the violet.