Illustration of the rescaled flux density uncertainties technique using synthetic data. a) Filled circles represent the flux densities at the different wavelengths with original flux density uncertainties. The dark line represents the best fit line (); the grey lines are fit lines of 100 out of 1000 synthetical bodies generated for the MC method. The bad quality of the fit is obvious, since the 70 and 100 μm datapoints are hardly fit by any of the single fit lines. Therefore, the reliability of the uncertainties of the output parameters is questionable. b) By rescaling the error bars by a factor of , the broadness of the distribution of single fit lines is increased, which covers now all datapoints. As a result, the output parameter fractional uncertainties are increased and therefore more realistic.