  We study how migration affects stars of a galaxy with a thin stellar disc and
thicker stellar components. The simulated galaxy has a strong bar and lasting
spiral arms. We find that the amplitude of the churning (change in angular
momentum) is similar for thin and thick components, and of limited amplitude,
and that stars of all components can be trapped at the corotation of the bar.
At the exception of those stars trapped at the corotation, we find that stars
that are far from their initial guiding radius are more likely so due to
blurring rather than churning effects. We compare the simulation to orbits
integration with a fixed gravitational potential rotating at a constant speed.
In the latter case, stars trapped at corotation are churned periodically
outside and inside the corotation radius, with a zero net average. However, as
the bar speed of the simulated galaxy decreases and its corotation radius
increases, stars trapped at corotation for several Gyrs can be churned outwards
on average. We study the location of extreme migrators (stars experimenting the
largest churning) and find that extreme migrators come from regions on the
leading side of the effective potential local maxima.
