Program: GS-2023A-Q-111

Hot Jupiters are blasted by stellar flux and typically exhibit large day-night contrasts of hundreds of Kelvin. Eastward flowing super-rotational jets are predicted to displace the hottest region east of the substellar point, which has been observed in many Spitzer Space Telescope phase curves. CoRoT-2b represents a rare case of a westward hotspot offset. Purely hydrodynamical models struggle to reproduce this behavior, and solutions involving patchy cloud coverage or interactions between the wind and magnetic field have been invoked. High-resolution observations with IGRINS will provide an independent method to confirm the western hotspot offset, and can be used to distinguish between the scenarios that create the hotspot offset by measuring the altitude of any cloud deck and the average surface velocity at different phases. As phase curves alone cannot distinguish between these scenarios, our observations will help with the physical interpretation of all hot-Jupiter phase curves.