This is a 2D simulation of the interaction of a low mass star
with the ISM. We show the evolution of the gas density
generated by a star during the AGB and PN phases moving at a
velocity of 20 km s-1 through an ISM with a density of n =
0.01 cm-3 (see Villaver, Garcia-Segura, & Manchado 2003). The
intensity scale is logarithmic. We can see the
formation of highly asymmetric shells that grows in size
mainly in the downstream direction. Note that the stellar wind
is changing all the time in the inner boundary condition as
the star experiences the thermal pulses during the AGB phase
(as indicated every time the pilot in the bottom left corner
is switched on).