Astrometric binaries (black) and CHT candidates (blue). Left panel: astrometric RV semi-amplitude and the estimated RV amplitude as functions of the orbital period, P (P − K₀ and $P-K_1^{*}$). The dashed red lines indicate the expected semi-amplitude for an edge-on 1 M_⊙ star with mass ratio q = 1 in a circular orbit. Black star symbols mark sources with K₀ significantly above the dashed line (see the main text). The vertical gap in the middle of the datasets reflects Gaia’s insensitivity near 1-year-period binary orbits and its harmonics. Right panel: photocentre significance (top panel) and apparent RVS magnitude (lower panel) as functions of distance ($\text{distance}-a_{\text{phot }}/{\sigma }_{a_{\text{phot }}}$ and distance − G_RVS).