Predicted maximum angular separation of a companion to RT Pav as a function of companion mass under the binary hypothesis assuming RT Pav’s 757 day LSP, and a primary mass of 1 M_⊙. Curves are shown for orbital eccentricities of 0.0, 0.3, and 0.6. The thick dashed line marks the adopted Gaia DR3 astrometric reflex motion detection threshold of 0.3 mas. Companion configurations above this threshold would typically induce a detectable astrometric signal and are therefore excluded by Gaia’s classification of RT Pav as a single star.