Absolute intensity calibrations of solar K-line profiles

Individual K-line profiles from elements of fine structure on the surface of the Sun are calibrated absolutely. The continuum calibrations of Labs and Neckel and of Houtgast and Namba are considered, and the average K-profile is scaled to that of White and Suemoto.The ranges of intensities across a high-resolution spectrogram are tabulated for various parts of the line profile. Although the spatially-averaged value for K ₃ of 4.2% of the continuum corresponds to a brightness temperature of 4155 K, minimum and maximum values were 3980 and 4360 K, respectively. Similarly, K _2v ranges from 4200 to 4560K, and K _2r from 4180 to 4460K in small elements about 1 arc sec across.