Masses Mℐ derived from fitting images ℐν of the isolated and embedded starless cores and protostellar envelopes (fits with free variable β). Two columns of panels (left, middle) display the masses derived for the resolved and unresolved images of the isolated models, whereas the third column of panels (right) presents results for the unresolved embedded models. Derived masses of the latter are underestimated by a factor of approximately 1.3 as a result of the conventional procedure of background subtraction (Sect. 5.2). See Fig. 8 for more details.