  Simulations with a 3D general circulation model (GCM) suggest that one
potential driver behind the observed radius inflation in hot Jupiters may be
the downward advection of energy from the highly irradiated photosphere into
the deeper layers. Here, we compare dynamical heat transport within the
non-inflated hot Jupiter WASP-43b and the canonical inflated hot Jupiter HD
209458b, with similar effective temperatures. We investigate to what extent the
radiatively driven heating and cooling in the photosphere (at pressures smaller
than 1 bar) influence the deeper temperature profile (at pressures between 1 to
700 bar). Our simulations with the new non-gray 3D radiation-hydrodynamical
model expeRT/MITgcm show that the deep temperature profile of WASP-43b is
associated with a relatively cold adiabat. The deep layers of HD 209458b,
however, do not converge and remain nearly unchanged regardless of whether a
cold or a hot initial state is used. Furthermore, we show that different flow
structures in the deep atmospheric layers arise. There, we find that WASP-43b
exhibits a deep equatorial jet, driven by the relatively fast tidally locked
rotation of this planet (0.81 days), as compared to HD 209458b (3.47 days).
However, by comparing simulations with different rotation periods, we find that
the resulting flow structures only marginally influence the temperature
evolution in the deep atmosphere, which is almost completely dominated by
radiative heating and cooling. Furthermore, we find that the evolution of
deeper layers can influence the 3D temperature structure in the photosphere of
WASP-43b. Thus, dayside emission spectra of WASP-43b may shed more light onto
the dynamical processes occurring at greater depths.
