  In this work we present a new scheme to study the tachyon dark energy model
using dynamical systems analysis by considering parametrization of the equation
of state(EoS) of the dark energy. Both the canonical and phantom field dynamics
are investigated. In our method we do not require any explicit form of the
tachyon potential. Instead of the potential we start with an approximate form
of the EoS of the tachyon field. This EoS is phenomenologically motivated and
contains some dimensionless parameters. Using our method we can construct the
dynamical system which gives rise to the time evolution of the universe. We
have considered two different parametrizations of the EoS and studied the phase
space dynamics in details. Our analysis shows Taylor series parametrization of
the EoS has serious cosmological limitations. Our proposal is generic in nature
and can be applied to other scalar field dark energy models.
