  We investigate the charged Vaidya spacetime with conformal symmetry by
classifying the horizons and finding its connection to Hawking temperature. We
find a conformal Killing vector whose existence requires the mass and electric
charge functions to be proportional, as well as linear in time. Solving the
Killing equations for the conformally transformed metric from the linear
charged Vaidya metric yields the required form of the conformal factor. From
the vanishing of the norm of the conformal Killing vector, we find three
conformal Killing horizons which, under the transformation, are mapped to the
Killing horizons of the associated static spacetime, if the spherical symmetry
is maintained. We find that the conformal factor is not uniquely determined,
but can take any function of the ratio of the radial coordinate to the
dynamical mass. As an example, we illustrate a static spacetime with our choice
of the conformal factor and explicitly show that the surface gravity of the
conformal Killing horizons, which is conformally invariant, yield the expected
Hawking temperature in the static spacetime. This static black hole spacetime
contains a cosmological horizon, but it is not asymptotically de Sitter. We
also investigate the case when the mass parameter is equal to the constant
electric charge. While in this case the standard pair of horizons, the loci of
the time component of the metric, degenerate, the conformal Killing horizons do
not degenerate. This therefore leads to a non-zero Hawking temperature in the
associated static spacetime.
