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Fig. 4.


Relative full-disc facular, umbral and penumbral contrasts (Eq. (2)) as calculated with ATLAS9 in LTE for U99 models and with NESSY in LTE and non-LTE for U99 and FAL99 models (faculae only). Each curve is derived from the corresponding curves in Fig. 2 and shows the impact on the relative contrasts produced by the change of code, radiative transfer treatment and the atmospheric model set. Shortward of about 150 nm the black curves are truncated because of the limitations of the ATLAS9 code at these wavelengths. NESSY contrasts are binned to the ATLAS9 spectral grid. The dashed lines designate the spectral domain of similar facular contrasts (see main text).

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