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 high 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 energy distribution (12 mu m less than or equal to lambda less than or equal to 2.7 mm) and the intensity profile at 100 mu m of IRAS 05380-0728. The model that gives the best fit to the observations requires a dust 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(inner), tau(100), and alpha, respectively, the outer radius, inner radius, optical depth at 100 mu m, and exponent of the power law in the density gradient n(r) proportional to r(-alpha). The derived density gradient, n(r) proportional to r(-0.75), is shallower than that predicted for 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 smaller than our far-infrared resolution, we relied on our polarimetry data to analyze the distribution of the scattering dust. From the distribution of the polarized intensity at the K band we derived an even shallower 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).