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Arxiv: The Asymmetric Bipolar Fe II Jet and H2 Outflow of TMC1A Resolved with JWST's NIRSpec IFU Published: 4/29/2024 2:33:06 AM Updated: 4/29/2024 2:33:06 AM

Paper abstract: (abridged) Protostellar outflows exhibit large variations in their structuredepending on the observed gas emission. This study analyzes the atomic jet andmolecular outflow in the Class I protostar, TMC1A to characterize morphologyand identify previously undetected spatial features with JWST's NIRSpec IFU. Inaddition to identifying a large number of Fe II and H2 lines, we have detectedthe bipolar Fe jet by revealing, for the first time, the presence of ared-shifted atomic jet. Similarly, the red-shifted component of the H2 slowerwide-angle outflow is observed. Both Fe II and H2 red-shifted emission exhibitsignificantly lower flux densities compared to their blue-shifted counterparts.Additionally, we report the detection of a collimated high-velocity (100 kms-1), blue-shifted H2 outflow, suggesting the presence of a molecular jet inaddition to the well-known wider angle low-velocity structure. The Fe II and H2jets show multiple intensity peaks along the jet axis, which may be associatedwith ongoing or recent outburst events. In addition to the variation in theirintensities, the H2 wide-angle outflow exhibits a "ring"-like structure. Theblue-shifted H2 outflow also shows a left-right brightness asymmetry likely dueto interactions with the surrounding ambient medium and molecular outflows.Using the Fe II line ratios, the extinction along the atomic jet is estimatedto be between Av = 10-30 on the blue-shifted side, with a trend of decreasingextinction with distance from the protostar. A similar Av is found for thered-shifted side, supporting the argument for an intrinsic red-blue outflowlobe asymmetry rather than environmental effects such as extinction. Thisintrinsic difference revealed by the unprecedented sensitivity of JWST,suggests that younger outflows already exhibit the red-blue side asymmetry morecommonly observed towards jets associated with Class II disks.