r/s (3D/projected separation) ratio vs distance χ² distribution for the four binaries with no Keplerian solutions: three from this study and one from the HARPS sample (WB24, shown in the top-left panel; Saglia et al. 2025). For all stellar pairs, the most probable r/s are large, from 5 to 50. When multiplying these ratios by the projected separations (s), the 3D minimum separation of the three pairs analysed in this Letter is ∼100 KAU.