The reflection-symmetric wiggle of the young protostellar jet HH 211
  HH 211 is a highly collimated jet originating from a nearby young Class 0
protostar. Here is a follow-up study of the jet with our previous observations
at unprecedented resolution up to ~ 0.3" in SiO (J=8-7), CO (J=3-2), and SO
(N_J=8_9-7_8). SiO, CO, and SO can all be a good tracer of the HH 211 jet,
tracing the internal shocks in the jet. Although the emissions of these
molecules show roughly the same morphology of the jet, there are detailed
differences. In particular, the CO emission traces the jet closer to the source
than the SiO and SO emissions. In addition, in the better resolved internal
shocks, both the CO and SO emission are seen slightly ahead of the SiO
emission. The jet is clearly seen on both sides of the source with more than
one cycle of wiggle. The wiggle is reflection-symmetric about the source and
can be reasonably fitted by an orbiting source jet model. The best-fit
parameters suggest that the source itself could be a very low-mass protobinary
with a total mass of ~ 60 M_Jup and a binary separation of ~ 4.6 AU. The
abundances of SiO and SO in the gas phase are found to be highly enhanced in
the jet as compared to the quiescent molecular clouds, even close to within 300
AU from the source where the dynamical time scale is <10 yrs. The abundance
enhancements of these molecules are closely related to the internal shocks. The
detected SiO is either the consequence of the release of Si-bearing material
from dust grains or of its formation via gas chemistry in the shocks. The SO,
on the other hand, seems to form via gas chemistry in the shocks.
