AMBER/VLTI squared visibility amplitudes of AB Dor A for J, H, and K bands (green, blue, and red data, respectively). The black continuous line corresponds to the visibilities resulting from the best fit of the data to a uniform disk model. The source is only partially resolved by the triplet A0-K0-G1, but sufficiently to constrain the angular size of AB Dor A to 0.62  ±  0.04 mas.