On the wavelength dependency of solar limb darkening (lambda lambda 303 to 1099 nm)

The limb-darkening data published by Neckel and Labs (1994) (5th-order polynomials P-5(mu), mu = Cos theta) are used to represent the limb darkening by the functions L(n) (mu), proposed first by Kourganoff(1949a). When plotted against wavelength, the coefficients of these functions show a rather low scatter and appear to be linear functions of either lambda(-1) or lambda(-5).