This is the author accepted manuscript.We started a survey with CHARA/MIRC-X and VLTI/GRAVITY to search for low mass
companions orbiting individual components of intermediate mass binary systems.
With the incredible precision of these instruments, we can detect astrometric
"wobbles" from companions down to a few tens of micro-arcseconds. This allows
us to detect any previously unseen triple systems in our list of binaries. We
present the orbits of 12 companions around early F to B-type binaries, 9 of
which are new detections and 3 of which are first astrometric detections of
known RV companions. The masses of these newly detected components range from
0.45-1.3 solar masses. Our orbits constrain these systems to a high astrometric
precision, with median residuals to the orbital fit of 20-50 micro-arcseconds
in most cases. For 7 of these systems we include newly obtained radial velocity
data, which help us to identify the system configuration and to solve for
masses of individual components in some cases. Although additional RV
measurements are needed to break degeneracy in the mutual inclination, we find
that the majority of these inner triples are not well-aligned with the wide
binary orbit. This hints that higher mass triples are more misaligned compared
to solar and lower mass triples, though a thorough study of survey biases is
needed. We show that the ARMADA survey is extremely successful at uncovering
previously unseen companions in binaries. This method will be used in upcoming
papers to constrain companion demographics in intermediate mass binary systems
down to the planetary mass regime.NASANational Science Foundation (NSF)European Research Council (ERC)Science and Technology Facilities Council (STFC)European Research Council (ERC
