WASP-121b's dayside atmosphere as viewed with ESPRESSO and CRIRES+

Stefan Pelletier ( Université de Montréal )

I will present the fruits of labour from my endeavours in Sweden as part of a CRAQ international internship. From this collaboration, I have assembled an unprecedented collection of high-resolution data targeting the ultra-hot Jupiter WASP-121b. I will show the synergy in combining two of the most powerful spectrographs in the world, one in the optical (ESPRESSO), and one in the infrared (CRIRES+). Optical light in particular allows us to probe for refractory atomic species (e.g., iron, nickel, vanadium) on WASP-121b, while infrared light is sensitive to volatile molecules (e.g., water, carbon monoxide). Here I will present the abundances and temperature structure retrieved for both facets of WASP-121b’s dayside atmosphere to compare differences between the east and west hemispheres of the planet. I will also discuss the results from combining these data to precisely determine crucial refractory and volatile abundance ratios (e.g., Fe/C, C/O) on WASP-121b, measurements that can shed new insights into how and where in the protoplanetary disc giant planets can form.