Global flow regimes of hot Jupiters

Context . The atmospheric dynamics of hot and ultrahot Jupiters are influenced by the stellar irradiation they receive, which shapes their atmospheric circulation and the underlying wave structures. Aims . We aim to investigate how variations in radiative and dynamical timescales influence global flow regimes, atmospheric circulation efficiency, and the interplay of wave structures across a curated sample of hot Jupiters. In particular, we explore a previously predicted transition in the global flow regime, where enhanced stellar irradiation suppresses the smaller-scale wave and eddy features that feed into superrotating jets and ultimately leads to simpler, day-to-night dominated flows. Methods . We simulated a suite of eight well-studied hot Jupiters with the THOR general circulation model, spanning equilibrium temperatures from about 1100 K to 2400 K. We developed a wavelet-based analysis method to decompose simulated wind fields into their underlying wave modes, which we validated on analytical examples. As a preliminary exploration of the flow regime of ultrahot Jupiters, we performed an additional simulation for WASP-121b, where the mean molecular weight was set to represent an atmosphere dominated by atomic hydrogen. Results . Our results confirm that increasing stellar irradiation diminishes the efficiency of atmospheric heat redistribution and weakens the contribution of smaller-scale eddy modes critical for sustaining superrotation. As equilibrium temperatures rise, large-scale modes dominate the atmospheric circulation, driving a transition from jet-dominated flows toward day-to-night circulation. Additionally, by artificially lowering the mean molecular weight, we partially restore circulation efficiency and reintroduce a more complex, multiscale flow pattern. These findings refine our understanding of how atmospheric circulation evolves with increasing irradiation and composition changes, offering a more nuanced framework for interpreting hot and ultrahot Jupiter atmospheres.