Decomposing the iron cross-correlation signal of the ultra-hot Jupiter WASP-76b in transmission using 3D Monte Carlo radiative transfer

ABSTRACT Ultra-hot Jupiters are tidally locked gas giants with dayside temperatures high enough to dissociate hydrogen and other molecules. Their atmospheres vastly non-uniform in terms of chemistry, temperature, dynamics, this makes their high-resolution transmission spectra cross-correlation signal difficult interpret. In work, we use the SPARC/MITgcm global circulation model simulate atmosphere ultra-hot Jupiter WASP-76b under different conditions, such as atmospheric drag absence TiO VO. We then employ a 3D Monte Carlo radiative transfer code, hires-mcrt, self-consistently iron (Fe i) lines at phases during transit. To untangle structure resulting map, decompose limb planet into four sectors, analyse each contributions separately. Our experiments demonstrate that an is primarily driven by its temperature structure, rotation, while being less sensitive precise distribution across atmosphere. also show previously published can be reproduced featuring condensation on leading limb. Alternatively, may explained substantial asymmetry between trailing limb, where not strictly required match data. Finally, compute Kp–Vsys maps simulated atmospheres, rotation dynamics lead multiple peaks displaced from zero planetary rest frame.