Near-infrared and Millimeter-wavelength Observations of Mol 160: A
  Massive Young Protostellar Core
  We have discovered two compact sources of shocked H2 2.12-micron emission
coincident with Mol 160 (IRAS 23385+6053), a massive star-forming core thought
to be a precursor to an ultracompact HII region. The 2.12-micron sources lie
within 2" (0.05 pc) of a millimeter-wavelength continuum peak where the column
density is >= 10e24 cm$^{-2}$. We estimate that the ratio of molecular hydrogen
luminosity to bolometric luminosity is > 0.2%, indicating a high ratio of
mechanical to radiant luminosity. CS J=2-1 and HCO$^+$ J=1-0 observations with
CARMA indicate that the protostellar molecular core has a peculiar velocity of
~ 2 km s$^{-1}$ with respect to its parent molecular cloud. We also observed 95
GHz CH3OH J=8$-7 Class I maser emission from several locations within the core.
Comparison with previous observations of 44-GHz CH3OH maser emission shows the
maser sources have a high mean ratio of 95-GHz to 44-GHz intensity. Our
observations strengthen the case that Mol 160 (IRAS 23385+6053) is a rapidly
accreting massive protostellar system in a very early phase of its evolution.
