2020ApJ...905..162T

We present ALMA (0.87 and 1.3 mm) and VLA (9 mm) observations toward the candidate intermediate-mass protostar OMC2-FIR3 (HOPS-370; L_bol ∼ 314 L_☉) at ∼0.''1 (40 au) resolution for the continuum emission and ∼0.''25 (100 au) resolution of nine molecular lines. The dust continuum observed with ALMA at 0.87 and 1.3 mm resolves a near edge-on disk toward HOPS-370 with an apparent radius of ∼100 au. The VLA observations detect both the disk in dust continuum and free-free emission extended along the jet direction. The ALMA observations of molecular lines (H₂CO, SO, CH₃OH, ¹³CO, C¹⁸O, NS, and H¹³CN) reveal rotation of the apparent disk surrounding HOPS-370 orthogonal to the jet/outflow direction. We fit radiative transfer models to both the dust continuum structure of the disk and molecular line kinematics of the inner envelope and disk for the H₂CO, CH₃OH, NS, and SO lines. The central protostar mass is determined to be ∼2.5 M_☉ with a disk radius of ∼94 au, when fit using combinations of the H₂CO, CH₃OH, NS, and SO lines, consistent with an intermediate-mass protostar. Modeling of the dust continuum and spectral energy distribution yields a disk mass of 0.035 M_☉ (inferred dust+gas) and a dust disk radius of 62 au; thus, the dust disk may have a smaller radius than the gas disk, similar to Class II disks. In order to explain the observed luminosity with the measured protostar mass, HOPS-370 must be accreting at a rate of (1.7-3.2) x 10^–5 M_☉ yr^–1.