Abstract
The effect of scattering by particles in a stationary medium surrounding a source is to in velocity the intrinsic gaussian profile of the source. The and strength of the wings depend oi dust properties and on the optical depth of the medium. Theoretical models can be used to estimate the of thejet to the line of sight, the source velocity, and the optical depth towards the source. We propose that the differences between [S II] and Ha line profiles in the jets associated with HH 34 and HH 47 are due to different optical depths to the line emitting regions, which could be due to different sizes for regions. The effects of scattering in reddening determinations that assume only attenuation of the light of the source are discussed. It is found that optical depth determined by assuming only attenuation is smaller than the actual optical depth of the region. Key : DUST - HERBIG-HARO OBJECTh - LINE PROFILE - RADIATION TRANSFER
