  The orbital stability of contact binary systems has been receiving
considerable attention recently. Theoretical studies indicate that merger is
likely to occur at very low mass ratios, but the actual mass ratio at which
merger may take place is likely to be variable and dependent on the mass of the
primary. We consider the effects of metal content on the orbital stability of
contact binary systems by modelling the gyration radius of a rotating and
tidally distorted primary component at various values of metallicity in the
range -1.25 to +0.5. We determine the instability mass ratio range for contact
binary systems with a low mass primary in the range 0.6M(sun) to 1.4M(sun) at
various metallicity levels and show that systems with low metallicity have an
instability mass ratio lower than those with higher metal content and therefore
are likely to be more stable. We illustrate the effect through light curve
analysis of two otherwise very similar contact binary systems, except for
different metallicity. While both would be considered unstable if metallicity
was not taken into consideration, only one remains in that category after
appropriate adjustments based on metallicity have been made.
