HIGH-RESOLUTION FAR-INFRARED OBSERVATIONS AND RADIATIVE-TRANSFER MODELS OF W3 IRS-4 AND IRS-5

Far-infrared continuum maps made with the Kuiper Airborne Observatory of W3 at 47 and 95 mu m show peaks identified with the mid-infrared so urces IRS 4 and IRS 5 and extended emission identified with the radio source W3(A). We have first taken the steepest radial scan profiles fr om the peaks at IRS 4 and IRS 5 to represent the objects as spherical clouds. Maximum entropy method deconvolutions indicate that these radi al scan profiles contain both compact cores and diffuse pedestals of e mission. Spherically symmetric radiative-transfer dust-cloud models we re created in an attempt to match these observed profiles. Models heat ed by central protostars or stars that match the 95 mu m data do not m atch extended emission in the 47 mu m scan profile for any assumed den sity distribution for either source. After the pedestals of diffuse em ission were removed from the original scans to form new ''core'' scans , models were found that approximately match the profiles at both wave lengths. Depending on the exact dust properties assumed for the cloud, the models have either uniform or power-law radial-density gradients with an exponent of -1. The cloud outer radii are 0.3-0.5 pc. Models f or IRS 5 have central stellar luminosities of 2.5-3.5 x 10(5) L., depe nding on the dust, and models for IRS 4 have 9.3 x 10(4) L. for both d ust types.