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Session 53 - Circumstellar Disks & Outflows Associated with YSOs.
Oral session, Tuesday, January 14
Piers 4/5,

[53.05] Colliding Winds and Infall Confinement of Protostellar Winds

F. P. Wilkin, S. W. Stahler (UC Berkeley)

We consider the hydrodynamic influence of the protostellar environment on the confinement of protostellar winds by modeling the collision of a stellar wind with anisotropic infall from a rotating cloud core. The stellar wind and infall collide supersonically, yielding a thin, radiative shocked shell. We calculate the structure of the shocked layer using a quasi-steady formulation similar to that used for stellar-wind bow shocks. At any time the shell structure is determined by simple conservation laws involving the fluxes of mass, momentum, and angular momentum of the incident wind and infall material, and including the effects of rotation and the stellar gravity. The gravitational forces are critical to the shell structure because in order for the infall ram pressure to be comparable to the wind ram pressure and allow normal force balance, the shell must be deep inside the gravitational well.

We find that self-consistent, bowshock-like steady-state solutions only exist when the stellar gravity is included. There are two solution families (an inner and an outer solution), which both move outward in quasi-steady fashion with time due to the evolving infall structure.

These solutions will be described and compared to new analytic solutions for bow shocks[1] and colliding winds[2] from spherically-symmetric sources. Fully non-steady calculations of the evolution will be presented in the future.

[1] Wilkin, F.P. 1996, ApJ, 459, L31. [2] Cantó, J., Raga, A.C., amp; Wilkin, F.P. 1996, ApJ, 469, 729

Program listing for Tuesday