Université de Montréal

Published purpose

Following the JWST ERS and Cycle 1 GO Announcement of Opportunity published on June 14, 2021, the CSA is providing funding via a Grant Agreement to the university to conduct their research using the JWST data. Hot Jupiters present an unprecedented opportunity to answer long-standing question regarding the formation processes of giant planets by measuring the carbon-to-oxygen ratio of their atmospheres. WASP-127b currently harbours both the strongest known water and carbon absorption features of any exoplanet to date as measured from HST and Spitzer. Unfortunately, those observations cannot distinguish between a CO2-rich low C/O case, or a CO-rich high C/O case. Both of these scenarios would have drastically different implications not only regarding WASP-127b's atmospheric chemistry, but also in terms of what mechanisms are at play during giant planet formation. We propose to observe a single transit of the ultra-puffy hot Jupiter WASP-127b using NIRSpec BOTS to determine what is the dominant carbon species of its atmosphere. Distinguishing between these scenarios will provide invaluable information regarding the formation process not only of the intriguing population of hot Jupiters, but also giant planets in general.