Far-infrared study of IRAS 00494+5617 and IRAS 05327-0457

Abstract

High angular resolution far-infrared observations at 143 and 185 µm, using the Tata Institute of Fundamental Research 1 m balloon-borne telescope, are presented for two Galactic star-forming complexes associated with IRAS 00494+5617 and IRAS 05327-0457. The latter map also reveals the cold dust in OMC-3. Both these regions are illuminated at the edges by high-mass stars with substantial UV flux. The HIRES (High-Resolution processing using Maximum Correlation Method) processed IRAS maps at 12, 25, 60, and 100 µm have also been presented for comparison. The present study is aimed at quantifying the role of the nearby stars vis-a-vis embedded young stellar objects in the overall heating of these sources. Based on the FIR observations at 143 and 185 µm carried out simultaneously with almost identical angular resolution, reliable dust temperature and optical depth maps have been generated for the brighter regions of these sources. Radiative transfer modeling in spherical geometry has been carried out to extract physical parameters of these sources by considering the observational constraints, such as spectral energy distribution, angular size at different wavelengths, dust temperature distribution, etc. It is concluded that for both IRAS 00494+5617 and IRAS 05327-0457, the embedded energy sources play the major role in heating them with finite contribution from the nearby stars. The best-fit model for IRAS 00494+5617 is consistent with a simple two-phase clump-interclump picture with ~5% volume filling factor (of clumps) and a density contrast of ≈80.