2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/181196The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) has monitored 37 sub-arcsecond binary systems to determine whether their Keplerian orbits are perturbed by faint astrometric companions to either star. Software has been developed to evaluate the regions in a companion mass-period phase space in which the PHASES observations can exclude the possibility of face-on orbit perturbations. We present results for 8 systems for which astrometric companions with masses as small as those of giant planets can be excluded.Accepted to ApJ, emulateapj 15 pagesAstrophysicstext