  ZZ PsA is a neglected bright southern contact binary system with maximum V
magnitude of 9.26. We present the first multi-band photometric analysis and
find the system to be in deep contact (>95%) with an extremely low mass ratio
of 0.078. The primary has a mass of 1.213 M? in keeping with its reported
spectral class of F6. In order to determine if ZZ PsA is a merger candidate we
outline the current status regarding the instability mass ratio and develop new
relationship linking the mass of the primary to the instability mass ratio of
the system and the degree of contact. We find that ZZ PsA along with two other
examples from the literature to be merger candidates while an additional three
require further observations to be confirmed as potential merger candidates.
