2013ApJ...771...71L

We report Submillimeter Array (SMA) observations of polarized 0.88 mm thermal dust emission and various molecular line transitions toward the early B-type (L_*∼ 2x10³ L_☉) star-forming region G192.16-3.84 (IRAS 05553+1631). The peak of the continuum Stokes-I emission coincides with a hot rotating disk/envelope (SO₂ rotational temperature T_rot^SO2 ∼ 84_–13⁺¹⁸ K), with a north-south velocity gradient. Joint analysis of the rotation curve traced by HCO⁺ 4-3 and SO₂19_1, 19_–180, 18_ suggests that the dense molecular gas is undergoing a spinning-up rotation, marginally bound by the gravitational force of an enclosed mass M_* + gas + dust_∼ 11.2-25.2 M_☉. Perpendicular to the rotational plane, a ≳ 100/cos (i) km/s (i ∼ 63°) high velocity molecular jet and a ∼15-20 km/s expanding biconical cavity were revealed in the CO 3-2 emission. The polarization percentage of the 0.88 mm continuum emission decreases toward the central rotating disk/envelope. The polarization angle in the inner ∼2'' (0.015 pc) disk/envelope is perpendicular to the plane of the rotation. The magnetic field lines, which are predominantly in the toroidal direction along the disk plane, are likely to be dragged by the gravitationally accelerated rotation.