ABSTRACT
The radiation we observe from an astronomical object displays a rather complex structure. In Figure 6.3 we showed the specific flux of the radiation observed from the Sun at the top of the atmosphere as a function of the wavelength. We see a large number of sudden dips on a background continuum, which can be well fitted by a blackbody distribution with a temperature of 5,778K. These sudden drops in flux at different wavelengths represent absorption lines. Besides the blackbody spectrum, which is produced by a source in thermal equilibrium, we also find several other forms of continuum spectra.
