Observations of B 335 in the Millimeter Continuum and the 226 GHz H 2 CO Line

The protostar B335 was observed in the 1.3 mm continuum and in the H2CO 312 → 211 line with an angular resolution of about 8. The mass of the inner envelope detected by the dust continuum emission is about 0.02 M⊙. The H2CO spectrum at the protostellar position shows a blue-skewed double peak profile, suggesting that the kinematics of the inner envelope is dominated by infall motion. When the blueshifted and the redshifted peaks were imaged separately, however, there is a small east-west displacement between the maximum positions. This displacement suggests that some part of the H2CO emission might come from the outflowing gas. A combined effect of the infalling envelope and the outflow on the radiative transfer is discussed. This effect can make the line profile asymmetry severer than what is expected from infall-only models.