2025RNAAS...9..260W

Stars with both a significant astrometric acceleration and no detected companion are candidates for having a compact object companion but they must first pass through the sieve of near-infrared interferometry. Psi Scorpii (ψ Sco) is a nearby A-type star that has amassed a number of astrometric anomalies while previous observations did not detect any companion. Here we report on a VLTI/GRAVITY observation in which we detected a companion to ψ Sco with a K band flux ratio of 3.5% ± 0.1% at a projected separation ρ = 78 mas ↔ 3.4 au. Isochrone fitting implies masses M_A ≃ 1.95M_⊙ and M_B ≃ 0.64M_⊙ and a system age of 630 Myr. The orbital motion with a period of about 10 yr can explain the astrometric anomalies of ψ Sco.