Visit ASIAA Homepage Registration Deadline: November 27, 2019 (Taiwan Time)
East-Asian ALMA Science Workshop 2019
February 19(Wed)-21(Fri), 2020
ASIAA, Taipei, Taiwan

Poster Presentation

Outflow Structures in the Vicinity of the Class 0 Low-mass Protostar in L483

Author(s): Takanori Fujita (The University of Tokyo)

Presenter: Takanori Fujita (The University of Tokyo)

Infalling envelope gas cannot accrete to a young protostar under the energy and angular momentum conservation. Thus, some mechanisms to extract the angular momentum of an infalling gas are required for the protostellar growth. Outflow is thought to be a potential mechanism for the angular momentum extraction, and thus, understanding the outflow structure is important for the star-formation study.
L483 (d=200 pc) is a class 0 protostellar core in the Aquila Rift. Previous studies revealed that the nearly edge-on disk-envelope structure along the southwest-northeast direction with the outflow along the southeast–northwest direction. In this study, we have investigated the outflow structures in the vicinity of the protostar with ALMA Cycle 4 data at a spatial resolution 40 au.
The CS (J=5–4) line traces the outflow cavity wall. The velocity structure of the CS line suggests the rotation motion of the outflow on a 100 au scale. It is consistent with the previous reports investigating the larger scale structure (1000 au). On the other hand, the opening angle of the outflow cavity and the direction of the outflow axis are found to be different between the results for the two scales. This result suggests that the outflow shape changes depending on the distance from the protostar.
In general, a parabolic model has been employed for outflow analyses. In fact, the outflow structure of L483 on a 1000 au scale was explained by the parabolic model. However, it seems difficult to explain the outflow structure in the vicinity of the protostar (100 au scale) with using the parabolic model. In this study, we modified the outflow model to reproduce the outflow structure in the vicinity of the protostar, and characterized its physical parameters.

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