Pre-registered predictions for Gaia DR4 residual images and source environments: companions of accelerating nearby stars and the nature of mid-infrared excesses

We record, before the Gaia DR4 release of 2 December 2026, falsifiable predictions for 114 nearby stars in the new DR4 residual images and gaia_source_environment table. For 80 stars within 25 pc with a Hipparcos–Gaia proper-motion anomaly (Kervella et al. 2022; Brandt 2021), we give the mass, G-band contrast and period of the companion required at projected separations of 0.3–2 arcsec, and a detection class. 31 stars should show a stellar companion with ΔG = 3–8 within 0.3–2 arcsec, 23 of them with no known companion that explains the acceleration. In 35 stars the companion must be substellar, so no point source is expected. For 34 stars within 100 pc with a WISE W3/W4 excess, we give our vetting (SIMBAD, VSX, kinematics, BANYAN Σ, unWISE centroid offsets, Cotten & Song 2016) and the expected appearance of the residual image: tenuous debris disks should leave a clean residual. The predictions will be checked against DR4 after release.