  Considering a Vaidya exterior spacetime, we study dynamical models of
prototype gravastars, made of an infinitely thin spherical shell of a perfect
fluid with the equation of state $p = \sigma$, enclosing an interior de Sitter
spacetime. We show explicitly that the final output can be a black hole, an
unstable gravastar, a stable gravastar or a "bounded excursion" gravastar,
depending on how the mass of the shell evolves in time, the cosmological
constant and the initial position of the dynamical shell. This work presents,
for the first time in the literature, a gravastar that emits radiation.
