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D.S. Smith (U Texas at Austin), K. Wood (Harvard-Smithsonian CfA), B. Whitney (Space Sciences Institute), S. Kenyon (CfA), K. Stassun (U Wisconsin)
Ground based imaging polarimetry and recent WFPC2 and NICMOS images of protostars have revealed very complex scattered light patterns. We are conducting detailed 3-D radiation transfer modeling of these sources to investigate the effects on image morphology of multiple illuminating sources and 3-D infalling envelopes that have been shaped by multiple outflows. We present model images for IRAS~04016+2610, IRAS~04248+2612, and T~Tau. We find that the scattered light pattern of IRAS~04016+2610 can be reproduced by scattering in an envelope with cavities carved by two sets of bipolar outflows, suggestive of an embedded binary system. IRAS~04248+2612 can be modeled with an envelope with a single bipolar cavity with the lower cavity offset from the upper. This break of axisymmetry is not surprising given the large precessing jets that are associated with this source. For T~Tau we have constructed scattered light models where the illumination of the surrounding envelope is by a binary with each source having a small circumstellar disk. We find that the asymmetries in the WFPC2 image of T~Tau can be reproduced if the disks in the binary system are misaligned. Our models demonstrate the necessity of a 3D scattering code in analysis of the complex geometries inherent in protostellar collapse.
This research is funded by the HST Archival Research Program, and the NSF REU program at the Harvard-Smithsonian Center for Astrophysics.