Result of the 2D Gaussian fit to the mid-IR emission from IRAS 20126+4104. (a) Distribution of the emission peaks at different epochs (from Table 1). The solid red line with PA=–60° represents a linear fit to the data. The solid green circle marks the 1.4 mm continuum peak, a good proxy for the protostar position. The dashed green line indicates the direction of the plane of the circumstellar disk. (b) Offsets of the mid-IR peaks, measured along the red line in the top panel, as a function of time. The horizontal green line indicates the offset corresponding to the projection of the green circle onto the red line in the top panel. The red sinusoid represents the best fit to the data.