Extraction and time variability of the free-free component. Left panel: flux density distribution of CX Tau, showing the dust emission fit (orange line) used to extract the free-free only estimates (yellow circles and arrows) from the measured flux densities and upper limits. Right panel: time variability of extrapolated free-free estimates at 1.3 cm. The extrapolation was performed assuming a free-free spectral index of 0.7 ± 0.1. The values in the plot are labeled with the observation they came from originally.