THE EMBEDDED YOUNG STARS IN THE TAURUS-AURIGA MOLECULAR CLOUD .2. MODELS FOR SCATTERED-LIGHT IMAGES

We describe near-infrared imaging observations of embedded young stars in the Taurus-Auriga molecular cloud. We find a large range in J-K an d H-K colors for these class I sources. The bluest objects have colors similar to the reddest T Tauri stars in the cloud; redder objects lie slightly above the reddening line for standard ISM dust and have appa rent K extinctions of up to 5 mag. Most of these sources also show ext ended near-IR emission on scales of 10''-20'', which corresponds to li near sizes of 1500-3000 AU. The near-IR colors and nebular morphologie s for this sample and the magnitude of linear polarization in several sources suggest scattered light produces most of the near-IR emission in these objects. We adopt the Terebey, Shu, and Cassen solution for a n infalling, rotating protostellar cloud and use a two-dimensional Mon te Carlo radiative transfer code to model the near-IR colors and image s for the embedded sample. Our results suggest mass infall rates that agree with predictions for cold clouds (T approximately 10-20 K) and a re generally consistent with rates estimated from radiative equilibriu m models in a previous paper (e.g., M approximately 2-10 x 10(-6) M. y r-1). For reasonable dust grain parameters, the range of colors and ex tinctions require flattened density distributions with polar cavities evacuated by bipolar outflows. These results support the idea that inf all and outflow occur simultaneously in deeply embedded, bipolar outfl ow sources. The data also indicate fairly large centrifugal radii, R(c ) approximately 100 AU, and large inclinations to the rotational axis, i approximately 60-degrees - 90-degrees, for a typical source. Our ce ntrifugal radius estimates agree with the disk radii inferred for many T Tauri stars in the Taurus-Auriga cloud. Better maps of polarization and molecular outflows in these objects can test our inclination esti mates.