Where do comets fit in the astrophysical puzzle?

Comets are one of our most direct links to the conditions present in the early Solar System.  They have retained volatiles with ice sublimation temperatures as low as ~20 K, not only indicating that they formed in cold regions of the solar system’s protoplanetary disk, but also that they have remained cold over the 4.5 Gyr history of the solar system.  However, an examination of the cometary population reveals characteristics that suggest their present-day compositions are affected by thermal processes.  An excellent example of these characteristics can be found in the short-period comet 22P/Kopff.  We present JWST/NIRSpec IFU spectroscopy of comet Kopff, and discuss the data in the context of the three primary volatiles in the cometary population: water, carbon dioxide, and carbon monoxide.  Compared to water, comet Kopff is depleted in CO, similar to many other short-period comets.  In contrast, the CO2-to-H2O ratio is typical for a comet of any type (short- or long-period), but the spatial distributions of these gases as observed with JWST indicate that they originate from distinctly different regions on the nucleus.  Therefore, the ratio CO2/H2O measured in the coma reflects the composition of a heterogeneous surface, rather than that of the bulk nucleus.  We discuss how sunlight-driven processes can reproduce these aspects of comet Kopff and others.  With respect to the three primary cometary volatiles, proto-planetary disk studies can be used to inform the studies of comets, and comets provide a local analog to circumstellar debris disks.