Program: GN-2006B-DD-1

Understanding how outflows moderate mass accretion onto a protostar has become a fundamental goal of modern stellar astrophysics because the efficiency of these flows will likely determine the stellar mass. Very high spatial resolution HST+STIS spectroscopy has revealed evidence for rotation in the inner jet channels of Classical T Tauri stars, which could mean that a connection between the disk and inner outflow may be responsible for driving the jets. However, this rotation hypothesis has met with skepticism, and alternative hypotheses based on the available data also seem plausible. We propose to observe one star with high enough S/N to search for the signature of jet rotation (RW Aur) and obtain follow-up observations of four other stars to determine the tangential velocities and thus the full 3-D velocity structure in the inner YSO jets (DG Tau, HV Tau C, T Tau, XZ Tau). These data will allow us to distinguish between scenarios where the velocity structure is caused by rotation versus turbulent motions or jet expansion for the inner YSO outflows.