Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoacán, Mexico
e-mail: f.wilkin@astrosmo.unam.mx
Abstract:
The time of protostellar wind breakout may be determined by the
evolution of the infalling flow, rather than any sudden
change in the central engine. I examine the transition from pure infall
to outflow, in the context of the inside-out collapse of a rotating
molecular cloud core. I have followed numerically the motion of
the shocked shell created by the impact of
a stellar wind and infalling gas.
These fully time-dependent calculations include cases both where
the shell falls back to the stellar surface,
and where it breaks out as a true outflow.
Assuming a wind launched from the protostellar surface, the
breakout time is determined in terms of the parameters describing the
wind (M•w, Vw) and collapsing cloud core
(ao, Ω).
The trapped wind phase consists of a wind sufficiently
strong to push material back from the stellar surface, but too weak
to carry the heavy, shocked infall out of the star's gravitational
potential. To produce a large-scale outflow,
the shocked material must be able to climb out of the star's gravitational
potential well, carrying with it the dense, swept-up infall.
