Relative astrometric shifts between the two epochs along α^* (x-axis) and δ (y-axis) for all the sources detected in the IRDIS FoV. The black dotted curve shows the expected motion of a pure background source with null proper motion when compared to a source co-moving with the target (the grey shaded region encompasses the uncertainty associated with this motion). The mean astrometric shifts of the probable background objects (blue crosses) detected in the data are shown as a thick blue cross, and those of HIP 81208 B and C are shown as a solid green triangle and a solid yellow square, respectively.