Visualization of the predicted positions of the candidate companion b of the star HIP 71865 (b Cen) under the proper motion and parallax model. A co-moving companion would remain at the position of the first epoch (blue circle) because orbital motion is not included. A field star with the modelled proper motion and parallax of nearby (mostly background) stars would be measured at the two later epochs at the two positions shown by the black triangles. The actual measured change in positions of the candidate are shown as orange triangles. The fact that these are much nearer to the blue distribution means this is likely to be a true companion, something that is properly quantified by our method. The contour lines show 50, 90, and 99% of the enclosed probability, reflecting the propagated uncertainty in the parallaxes, proper motions, and BEAST position measurements. The marginal likelihoods are shown on both axes. This visualization does not show the covariances between the measurements at different epochs, which are nonetheless taken into account by our method (see Eq. (A.4)).