  The formation of circumplanetary disks is central to our understanding of
giant planet formation, influencing their growth rate during the post-runaway
phase and observability while embedded in protoplanetary disks. We use 3D
global multifluid radiation hydrodynamics simulations with the FARGO3D code to
define the thermodynamic conditions that enable circumplanetary disk formation
around Jovian planets on wide orbits. Our simulations include stellar
irradiation, viscous heating, static mesh refinement, and active calculation of
opacity based on evolving dust fluids. We find a necessary condition for the
formation of circumplanetary disks in terms of a mean cooling time: when the
cooling time is at least one order of magnitude shorter than the orbital time
scale, the specific angular momentum of the gas is nearly Keplerian at scales
of $R_{\rm{Hill}}/3$. We show that the inclusion of multifluid dust dynamics
favors rotational support because dust settling produces an anisotropic opacity
distribution that favors rapid cooling. In all our models with radiation
hydrodynamics, specific angular momentum decreases as time evolves in agreement
with the formation of an inner isentropic envelope due to compressional
heating. The isentropic envelope can extend up to $R_{\rm{Hill}}/3$ and shows
negligible rotational support. Thus, our results imply that young gas giant
planets may host spherical isentropic envelopes, rather than circumplanetary
disks.
