Dissecting Massive Protostars: Testing Theoretical Models with Flux Density Profiles

We present an analysis of infrared images of massive protostars, selected from the SOFIA Massive (SOMA) Star Formation survey, to characterize their flux density profiles. We focus on SOFIA-FORCAST images at 31 and 37 microns that probe deep into the protostellar cores. We first measure flux density profiles along outflow axes of the sources, as previously determined from molecular line observations. Generally the near-facing outflow cavity appears brighter than the far-facing cavity, because of extinction in the core envelope. We then compare these observational results to predictions of theoretical models and radiative transfer simulations of the massive protostars forming in the context of the Turbulent Core Accretion model (McKee & Tan 2003; Zhang & Tan 2018). This analysis determines the validity of the model, and furthermore examines how the extra information available from flux density profiles can improve constraints that are derived solely from spectral energy distribution fitting.