  The recent discovery of a spectacular dust plume in the system 2XMM
J160050.7-514245 (referred to as "Apep") suggested a physical origin in a
colliding-wind binary by way of the "Pinwheel" mechanism. Observational data
pointed to a hierarchical triple-star system, however several extreme and
unexpected physical properties seem to defy the established physics of such
objects. Most notably, a stark discrepancy was found in the observed outflow
speed of the gas as measured spectroscopically in the line-of-sight direction
compared to the proper motion expansion of the dust in the sky plane. This
enigmatic behaviour arises at the wind base within the central Wolf-Rayet
binary: a system that has so far remained spatially unresolved. Here we present
an updated proper motion study deriving the expansion speed of Apep's dust
plume over a two-year baseline that is four times slower than the spectroscopic
wind speed, confirming and strengthening the previous finding. We also present
the results from high-angular-resolution near-infrared imaging studies of the
heart of the system, revealing a close binary with properties matching a
Wolf-Rayet colliding-wind system. Based on these new observational constraints,
an improved geometric model is presented yielding a close match to the data,
constraining the orbital parameters of the Wolf-Rayet binary and lending
further support to the anisotropic wind model.
