Science with an ngVLA: New Frontiers in Protostellar Multiplicity with
  the ngVLA
  The ngVLA will enable significant advances in our understanding of the
formation and evolution of multiple star systems in the protostellar phase,
building upon the breakthroughs enabled by the VLA. The high-sensitivity and
resolution at 3~mm wavelengths and longer will enable closer multiple systems
to be discovered in the nearby star forming regions.
  The ngVLA is incredibly important for multiplicity studies because dust
opacity at short wavelengths ($<$3~mm) can hide multiplicity and the long
wavelengths are needed to reveal forming multiples in the youngest systems. The
samples sizes can be expanded to encompass star forming regions at distances of
at least 1.5~kpc, enabling statistical studies that are on par with studies of
field star multiplicity. We verify the capability of the ngVLA to detect and
resolve multiple star systems at distances out to 1.5~kpc using empirical
examples of systems detected by the VLA and scaling them to greater distances.
We also use radiative transfer models and simulations to verify that the ngVLA
can resolve close binary systems from their dust emission at these distances.
The ngVLA will also have excellent imaging capability and the circum-multiple
environments can also be examined in great detail.
