Peak-normalized PIONIER continuum model images. The dashed white lines represent the ±3σ MCMC uncertainties on the PA of the azimuthal modulation. A description of the model is given in Sect. 3. The central object is not displayed in order to enhance the circumstellar emission. The contrast reported in Sect. 3.3 is calculated from the peak-normalized brightness distribution map as the ratio between the brightest pixel in the map and the corresponding centro-symmetric position in the disk. We report the standard deviation for the mean contrast value across the different PIONIER epochs.