Example of a grid fit, in this case corresponding to Figure 1. On the left, we show the grid of potential companion positions that we searched in terms of goodness of fit, as quantified by the χ². The primary star, which was fixed at position (0,0) during the fit, is shown by a blue star. The black circle shows the (x,y) position of the companion in the best-fitting model. On the right, we show the grid in terms of companion significance. This allowed us to determine whether a companion determined by the best-fitting model was significant in terms of its flux.