  We analyze the general model of a radiating star in general relativity. A
group analysis of the under determined, nonlinear partial differential equation
governing the model's gravitational potentials is performed. This analysis is
an extension of previous group analyses carried out and produces new group
invariant solutions. We find that the gravitational potentials depend on
exponential functions owing to the choice of the Lie symmetry generator. The
fundamental boundary equation to be solved is in general a Riccati equation.
Several new exact families of solutions to the boundary condition are
generated. Earlier models of Euclidean stars and generalized Euclidean stellar
models are regained as special cases. Linear equations of state can be found
for shear-free and shearing spacetimes.
