Top: apparent displacement of the center of light of the δ Vel Aab eclipsing pair relative to B as a function of the orbital phase (the secular displacement of B has been subtracted). The two discrepant measurements around φ = 0.7 are discussed in Sect. 4.1. Bottom: ratio of the photometric fluxes of δ Vel A and B in the NACO narrow-band 2.17 μm filter (Table 2), normalized to the median measured ratio (10.372). For both plots, the solid curves are the predictions of the model presented in Paper III, and not the result of a fit to the data.