  We study a new rheological model describing flows of melts and solutions of
incompressible viscoelastic polymeric media in an external uniform magnetic
field in the presence of a temperature drop and a conduction current. We find
an asymptotic representation of the spectrum of the linear problem resulting
from the linearization of the initial boundary value problem in an infinite
plane channel about a Poiseuille-type flow. For this Poiseuille-type flow we
also find the parameter domain of linear Lyapunov's stability.
