Climate Patterns of Spin-Orbit Resonant Exoplanets Around Low-Mass Stars

M dwarfs are the most promising candidates for finding habitable worlds through atmospheric characterization. Planets in the habitable zone of low-mass stars experience intense tidal forcings and often become tidally locked. Despite the majority of research being centered on the climate dynamics of synchronously rotating planets in this scenario, synchronous rotation is not an inevitable outcome of tidal locking. Several different circumstances can result in an asynchronous rotation, and in some instances can lead to spin-orbit resonances (SORs).
We explore the climates of two different spin-orbit resonant scenarios with a coupled atmosphere-ocean general circulation climate model. Given the crucial role played by the oceans in shaping planetary climate, we adopt two different ocean tidal forcing parameterizations for each SOR scenario. Each of these cases are simulated with both a dynamic ocean and a thermodynamic ocean.
Our findings reveal striking differences between the analyzed resonant case and the commonly studied synchronous rotation case. Periodic climate patterns are observed, with climatic features such as clouds and rainfall exhibiting a 60$^\circ$ longitudinal shift relative to the substellar point. The evolution of quantities such as thermal emission and reflected light during a stellar period is noteworthy from the observational point of view, showing appreciable differences compared to the synchronous rotation scenario.