The Butterfly Effect: Determining the distribution of ices across a young disk to constrain planet formation

Young disks (Class I) orbiting nascent stars are the birthplaces of planets. In order to link the elemental composition of exoplanets, that JWST will provide in plenty, to their formation history, one needs to determine the chemical composition of both the gas and solids across the disk. With ALMA a stunning progress has been made to map the gas content of disks, but the distribution and compositions of ices remains poorly known. We aim to target IRAS 04302 (the Butterfly Star) with MIRI MRS and NIRSpec IFU, to map the major carbon and oxygen carriers in the ice phase: CO, CO2, CH4 and H2O. The exact edge-on geometry and large size makes this young disk uniquely suited to unveil for the first time the vertical and radial structure of the ices. We will obtain the radial and vertical location of the CO, CO2, H2O snow surfaces, which are setting the C/O ratio of the gas and dust. These observations will demonstrate the impact that JWST will have on the studies of planet formation.