  This paper is concerned with the Cauchy problem of Navier-Stokes equations
for compressible viscous heat-conductive fluids with far-field vacuum at
infinity in $\R^3$. For less regular data and weaker compatibility conditions
than those proposed by Cho-Kim \cite{CK2006}, we first prove the existence of
local-in-time solutions belonging to a larger class of functions in which the
uniqueness can be shown to hold. Next, we prove that the local strong solution
is in fact a classical one away from the initial time. Then, we establish the
global well-posedness of classical solutions in the case when the initial
density is suitably small. The exponential decay estimates of higher-order
derivatives are also obtained.
