The two hot corinos of the SVS13-A protostellar binary system:
  counterposed siblings
  We present ALMA high-angular resolution ($\sim$ 50 au) observations of the
Class I binary system SVS13-A. We report images of SVS13-A in numerous
interstellar complex organic molecules: CH$_{\rm 3}$OH, $^{13}$CH$_{\rm 3}$OH,
CH$_{\rm 3}$CHO, CH$_{\rm 3}$OCH$_{\rm 3}$, and NH$_{\rm 2}$CHO. Two hot
corinos at different velocities are imaged in VLA4A (V$_{sys}$= +7.7 km
s$^{-1}$) and VLA4B (V$_{sys}$= +8.5 km s$^{-1}$). From a non-LTE analysis of
methanol lines we derive a gas density of 3 $\times$ 10$^8$ cm$^{-3}$, and gas
temperatures of 140 K and 170 K for VLA4A and VLA4B, respectively. For the
other species the column densities are derived from a LTE analysis. Formamide,
which is the only N-bearing species detected in our observations, is more
prominent around VLA4A, while dimethyl ether, methanol and acetaldehyde are
associated with both VLA4A and VLA4B. We derive in the two hot corinos
abundance ratios of $\sim$ 1 for CH$_{\rm 3}$OH, $^{13}$CH$_{\rm 3}$OH, and
CH$_{\rm 3}$OCH$_{\rm 3}$, $\sim$ 2 for CH$_{\rm 3}$CHO, and $\sim$ 4 for
NH$_{\rm 2}$CHO. The present dataset supports a chemical segregation between
the different species inside the binary system. The emerging picture is that of
an onion-like structure of the two SVS13-A hot corinos, caused by the different
binding energies of the species, also supported by ad hoc quantum chemistry
calculations. In addition, the comparison between molecular and dust maps
suggests that the interstellar complex organic molecules emission originates
from slow shocks produced by accretion streamers impacting the VLA4A and VLA4B
disks and enriching the gas-phase component.
