We know planetary systems form from disks of gas and dust. ALMA imaging provides exquisite spatial detail in many planet forming disks, but the dust and carbon monoxide (CO) datasets are subject to uncertain depletion and gas-phase abundance. The ALMA images do not connect directly to the most fundamental basic properties of these disks: their masses and elemental abundances.

PRIMA connects water, oxygen, and carbon in protoplanetary disks with compositions of exoplanet atmospheres to understand how and where planets form.

PRIMA will survey 200 disks with high-resolution spectroscopy. For each, the 24-235 μm spectrum will measure the water distribution (Objective 1A) and total disk mass using the HD transition (Objective 1B). The water distribution across the various temperature zones constrains theories of planetesimal formation and delivery of water to the habitable zone. Obtaining total gas mass allows inferences of absolute carbon and oxygen abundances, which can then be compared with measured exoplanetary abundances, testing our models of planet formation.