Complex structure of a proto-brown dwarf
  We present ALMA $^{12}$CO (2-1), $^{13}$CO (2-1), C$^{18}$O (2-1) molecular
line observations of a very young proto-brown dwarf system, ISO-OPH 200. We
have conducted physical+chemical modelling of the complex internal structure
for this system using the core collapse simulations for brown dwarf formation.
The model at an age of $\sim$6000 yr can provide a good fit to the observed
kinematics, spectra, and reproduce the complex structures seen in the moment
maps. Results from modelling indicate that $^{12}$CO emission is tracing an
extended ($\sim$1000 au) molecular outflow and a bright shock knot, $^{13}$CO
is tracing the outer ($\sim$1000 au) envelope/pseudo-disc, and C$^{18}$O is
tracing the inner ($\sim$500 au) pseudo-disc. The source size of $\sim$8.6 au
measured in the 873$\mu$m image is comparable to the inner Keplerian disc size
predicted by the model. A 3D model structure of ISO-OPH 200 suggests that this
system is viewed partially through a wide outflow cavity resulting in a direct
view of the outflow and a partial view of the envelope/pseudo-disc. We have
argued that ISO-OPH 200 has been mis-classified as a Class Flat object due to
the unusual orientation. The various signatures of this system, notably, the
young $\sim$616 yr outflow dynamical age and high outflow rate
($\sim$1$\times$10$^{-7}$ M$_{\odot}$ yr$^{-1}$), silicate absorption in the
10$\mu$m mid-infrared spectrum, pristine ISM-like dust in the envelope/disc,
comparable sizes of the extended envelope and outflow, indicate that ISO-OPH
200 is an early Class 0 stage system formed in a star-like mechanism via
gravitational collapse of a very low-mass core.
