Digging into the Interior of Hot Cores with ALMA (DIHCA). II. Exploring
  the Inner Binary (Multiple) System Embedded in G335 MM1 ALMA1
  We observed the high-mass protostellar core G335.579-0.272 ALMA1 at
${\sim}200$ au (0.05") resolution with the Atacama Large
Millimeter/submillimeter Array (ALMA) at 226 GHz (with a mass sensitivity of
$5\sigma=0.2$ M$_\odot$ at 10 K). We discovered that at least a binary system
is forming inside this region, with an additional nearby bow-like structure
(${\lesssim}1000$ au) that could add an additional member to the stellar
system. These three sources are located at the center of the gravitational
potential well of the ALMA1 region and the larger MM1 cluster. The emission
from CH$_3$OH (and many other tracers) is extended ($>1000$ au), revealing a
common envelope toward the binary system. We use CH$_2$CHCN line emission to
estimate an inclination angle of the rotation axis of $26^\circ$ with respect
to the line of sight based on geometric assumptions and derive a kinematic mass
of the primary source (protostar+disk) of 3.0 M$_\odot$ within a radius of 230
au. Using SiO emission, we find that the primary source drives the large scale
outflow revealed by previous observations. Precession of the binary system
likely produces a change in orientation between the outflow at small scales
observed here and large scales observed in previous works. The bow structure
may have originated by entrainment of matter into the envelope due to widening
or precession of the outflow, or, alternatively, an accretion streamer
dominated by the gravity of the central sources. An additional third source,
forming due to instabilities in the streamer, cannot be ruled out as a
temperature gradient is needed to produce the observed absorption spectra.
