  The background evolution of an accelerated, dark energy dominated universe is
aptly described by non-canonical tachyon scalar field models. The accelerated
expansion of the universe is determined by the choice of a suitable scalar
field potential; in the case of a tachyon field, a 'runaway' potential. In the
absence of a fundamental theory, dark energy properties are studied in a
phenomenological approach. This includes determining the model parameters using
observations and to probe the allowed deviation from the cosmological constant
model. In this paper, we present constraints on tachyon scalar field parameters
from low redshift data for two different scalar field potentials. These scalar
field potentials have been crucial in tachyon dark energy studies. The datasets
considered in this paper include the supernova type Ia data, independent
measurements of the Hubble parameter and the Baryon Acoustic Oscillation data.
In this paper, we present constraints on tachyon field parameters using these
observations and their combination. A combination of the datasets indicates
that those model parameters are preferred which emulate the cosmological
constant model. The initial value of the scalar field, in the unit of the
Hubble constant, is bounded from below and does not require fine-tuning at
larger values.
