AN INFRARED STUDY OF THE STAR-FORMING REGION IRAS-05380-0728

We have observed the embedded young stellar object IRAS 05380-0728 at 100 mu m with high spatial resolution (40 ''). We have also obtained h igh angular resolution (1 ''.2) near-infrared polarimetry at 1.65 and 2.2 mu m of the infrared source (IRS 1) and its associated reflection nebulosity (Re 50N). IRAS 05380-0728 is resolved at 100 mu m. We have used a radiative transfer code in order to model both the spectral ene rgy distribution (12 mu m less than or equal to lambda less than or eq ual to 2.7 mm) and the intensity profile at 100 mu m of IRAS 05380-072 8. The model that gives the best fit to the observations requires a du st cloud of the following characteristics: R(outer) = 0.3 pc, R(inner) = 5 x 10(-4) pc, tau(100) = 0.07, alpha = 0.75, where R(outer), R(inn er), tau(100), and alpha, respectively, the outer radius, inner radius , optical depth at 100 mu m, and exponent of the power law in the dens ity gradient n(r) proportional to r(-alpha). The derived density gradi ent, n(r) proportional to r(-0.75), is shallower than that predicted f or the presence of an infalling envelope (alpha = 1.5), which has been suggested to coexist with dense cores associated with low-mass young stellar objects. For distances to the central illuminating source smal ler than our far-infrared resolution, we relied on our polarimetry dat a to analyze the distribution of the scattering dust. From the distrib ution of the polarized intensity at the K band we derived an even shal lower dust density gradient within a radius of r less than or equal to 6 '' from IRS 1, namely, n(r) proportional to r(-0.3), r(0.0).