Modeling the continuum emission from class 0 protostellar sources

Class 0 sources are objects representing the earliest phase of protostellar evolution. Since these objects are highly obscured by an extended dusty envelope, they can be observed mainly in the far-infrared to mm wavelength range. The analysis of their spectral energy distributions (SEDs) with wide wavelength coverage allows to determine their bolometric temperatures and luminosities. However, a more detailed physical interpretation of the internal physical structure of these objects requires radiative transfer modeling. Here we present the SED modeling results for a sample of nine Class 0 sources located in the Perseus and Orion molecular clouds. The SEDs have been simulated using a radiative transfer code based on the Monte Carlo method. We find that a spherically symmetrical model for the youngest Class 0 sources allows to reproduce the observed SEDs reasonably well. Using our models of these sources we derive their masses, density distributions, sizes, etc. The density structure of ? ? r-2 for the collapsing cores at young ages evolves to ? ? r-3/2 at later stages.