X-ray processing of a realistic ice mantle can explain the gas abundances in protoplanetary disks.

The Atacama Large Millimeter Array has allowed a detailed observation of molecules in protoplanetary disks, which can evolve toward solar systems like our own. While CO, [Formula: see text], HCO, and [Formula: see text] are often abundant species in the cold zones of the disk, [Formula: see text] or [Formula: see text] are only found in a few regions, and more-complex organic molecules are not observed. We simulate, experimentally, ice processing in disks under realistic conditions, that is, layered ices irradiated by soft X-rays.