  Dynamical stellar-evolution modeling through the AGB phase reveals that
radial pulsations with very fast-growing amplitudes develop if the luminosity
to mass ratio of stars with tenuous envelopes exceeds a critical limit. An
instability going nonlinear already after a few pulsation cycles might qualify
as a source of the superwind - postulated to shed a substantial part of a
star's envelope over a very short time - of hitherto persistently mysterious
nature.
