A Unified Model for Bipolar Outflows from Young Stars: Kinematic and Mixing Structures in HH 30

Abstract

The young stellar source HH 30 is a textbook example of an ionic optical jet originating from a disk in an edge-on system shown by the Hubble Space Telescope. It has a remnant envelope in ^12 CO observed by the Atacama Large Millimeter/submillimeter Array. The optical jet is characterized by its narrow appearance, large line width at the base, and high temperature inferred from line diagnostics. Three featured structures can be identified, most evident in the transverse position–velocity diagrams: an extremely-high-velocity wide-angle wind component with large spectral widths in the optical, a very-low-velocity ambient surrounding medium seen in ^12 CO, and a low-velocity region traced by ^12 CO nested both in velocity and location between the primary wind and ambient environment. A layered cavity with multiple shells forms nested morphological and kinematic structures around the optical jet. The atomic gas originating from the innermost region of the disk attains a sufficient temperature and ionization to emit brightly in forbidden lines as an optical jet. The wide-angle portion expands, forming a low-density cavity. The filamentary ^12 CO encompassing the wind cavity is mixed and advected inward through the action of the magnetic interplay of the wide-angle wind with the molecular ambient medium. The magnetic interplay results in the layered shells penetrating deeply into the vast cavity of tenuous atomic wind material. The HH 30 system is an ideal manifestation of the unified wind model of Shang et al. (2020, 2023), with clearly distinguishable atomic and molecular species mixed through the atomic lightly ionized magnetized wind and the surrounding cold molecular ambient material.

Keywords

• Stellar jets
• Stellar winds
• Stellar wind bubbles
• Collapsing clouds
• Young stellar objects
• Protostars