A synergistic collaboration between protoplanetary disk modelers and comet scientists aims to establish a stronger connection between their respective fields. As some of the best-preserved (though not necessarily pristine) remnants from the early solar system, comets are extensively studied. Astronomical spectroscopy and in situ investigations, especially the Rosetta mission, yield the relative abundances (C₂H₆/H₂O; CH₃OH/H₂O; HDO/H₂O, etc.) of parent (i.e. originally stored as ices in comet nuclei) volatiles. While empirical knowledge is being accumulated, most observational papers on comets offer a predominantly qualitative interpretation of measured abundances in terms of our solar system’s origins.

Like comet observations, chemical modeling of protoplanetary disks is driven by the challenge to understand the conditions for planetary system formation. Despite this common motivation, disk models have improved largely in parallel, not “in sync” with comet studies. The clear need to bring comet measurements and disk modeling into closer contact motivates this project.

The team will summarize relevant studies of parent volatiles observed in comets. Since observed volatile abundances are likely byproducts of both formative conditions and post-formative evolution, the team will outline those measurements most suitable for a meaningful comparison with disk models. The team will also discuss the advancements in modeling the chemical evolution of protoplanetary disks following molecular cloud core collapse. Comet data will then be interpreted in the context of the best disk modeling networks (chemical and physical).

ISSI is a truly unique venue for such a cross-discipline endeavor. The proposed models-data synergy, including input for planning future space missions, is a priority to ISSI. The comet-disk connection is a very timely topic with the recent Rosetta mission, recent and forthcoming improvements in detectors for spectroscopy on comets, and the Atacama Large Millimeter/submillimeter Array (ALMA) opening a new window to spatially resolved emission from both protostellar disks and comets. It is time to include disk modelers as major contributors to comet science. The project is highly relevant to the AsTroMap European Astrobiology Roadmap, released in 2016.