  Molecular clouds in the interstellar medium suffer gravitational
instabilities that lead to the formation of one or multiple stars. A recently
formed star inside a cold cloud communicates its gravitational force to the
surrounding environment and soon an accretion flow falling into the star
develops. After their formation, all stars soon eject a wind of gas that
interacts with the external accretion flow. This interaction produces a shock
wave that evolves with time. The work presented in this article formulates a
simple prescription for the evolution of this interaction. With the aid of this
model we construct a few radio continuum maps of the source.
