Scattered Light Models of Protostellar Envelopes: Multiple Outflow Cavities and Misaligned Circumstellar Disks

Abstract

Ground-based imaging, imaging polarimetry, and recent Hubble Space Telescope WFPC2 and NICMOS images of protostars have revealed very complex scattered light patterns that cannot be entirely explained by two-dimensional radiation transfer models. We present here for the first time radiation transfer models of T Tau and IRAS 04016+2610 that are fully three-dimensional, with the aim of investigating the effects on image morphology of multiple illuminating sources and infalling envelopes that have been shaped by multiple outflows. For T Tau we have constructed scattered light models where the illumination of the surrounding envelope is by a binary, with each source surrounded by its own small circumstellar disk or envelope. We find that the asymmetries in the WFPC2 image of T Tau can be reproduced if the disks in the binary system are misaligned, consistent with a recently discovered bipolar outflow believed to originate from the secondary. For IRAS 04016+2610 we find that the observed scattered light pattern can be reproduced by scattering in an envelope with cavities carved by two sets of bipolar outflows, suggestive of an embedded binary system.