Angular momentum in bipolar outflows: dynamical evolutionary model

Abstract

We model molecular outflows produced by the time dependent interaction between a stellar wind and a rotating cloud envelope in gravitational collapse, studied by Ulrich. We consider spherical and anisotropic stellar winds. We assume that the bipolar outflow is a thin shocked shell, with axial symmetry around the cloud rotation axis and obtain the mass and momentum fluxes into the shell. We solve numerically a set of partial differential equations in space and time, and obtain the shape of the shell, the mass surface density, the velocity field, and the angular momentum of the material in the shell. We find that there is a critical value of the ratio between the wind and the accretion flow momentum rates $\beta$ that allows the shell to expand. As expected, the elongation of the shells increase with the stellar wind anisotropy. In our models, the rotation velocity of the shell is the order to 0.1 - 0.2 km s${}^{-1}$, a factor of 5-10 lower than the values measured in several sources. We compare our models with those of Wilkin and Stahler for early evolutionary times and find that our shells have the same sizes at the pole, although we use different boundary conditions at the equator.

References in corpus (14)

• Locating the Launching Region of T Tauri Winds: The Case of DG Tau
• The HH30 edge-on T Tauri star A rotating and precessing monopolar outflow scrutinized by ALMA
• Bipolar molecular outflows driven by hydromagnetic protostellar winds
• Rotation and Outflow motions in the very low-mass Class 0 protostellar system HH 211 at subarcsecond resolution
• Rotating molecular outflows: the young T Tauri star in CB26
• The outflow history of two Herbig-Haro jets in RCW 36: HH 1042 and HH 1043
• Rotation in the NGC 1333 IRAS 4C Outflow
• A 100 au-Wide Bipolar Rotating Shell Emanating From The HH 212Protostellar Disk: A Disk Wind?
• Kinematics of the Outflow From The Young Star DG Tau B: Rotation in the vicinities of an optical jet
• A young protoplanetary disk in the Bok globule CB26?
• A rotating molecular jet in Orion
• A rotating molecular jet from a Perseus protostar
• Transverse velocity shifts in protostellar jets: rotation or velocity asymmetries?
• Trapped Protostellar Winds and their Breakout

Cited by in corpus (6)

• Modeling the CO outflow in DG Tau B: Swept-up shells versus perturbed MHD disk wind
• JWST study of the DG Tau B disk wind candidate: I -- Overview and Nested H${}_2$/CO outflows
• Steady Wind-Blown Cavities within Infalling Rotating Envelopes: Application to the Broad Velocity Component in Young Protostars
• A resolved rotating disk wind from a young T Tauri star in the Bok globule CB26
• A disk-wind driving the rotating molecular outflow in CB 26
• ALMA observations and modeling of the rotating outflow in Orion Source I