A Retrieval Framework for Observationally Constraining the Parameters of Circumplanetary Disks

Abstract

As they form, giant planets are surrounded by disks of gas and dust sourced from the background circumstellar disk. Although there have been few detections to date, upcoming instruments are likely to discover many more of these systems in the coming decades. Accurate spectral modeling will enable these observations to constrain the properties of these forming systems. Towards this end, we have constructed a semianalytic model for the structure and radiative signatures of geometrically thick circumplanetary disks and their planet hosts. Fitting these radiative signatures to synthetic observations of a two-dimensional disk model then quantifies the parameter constraints that can be derived (subject to model assumptions). This machinery provides estimates of the values and uncertainties in system parameters, and some combinations of parameters have significantly smaller uncertainties than others. This model is then used to fit observations of real protoplanets, with good results. The derived parameters provide useful context about the local extinction, formation history, and initial entropy of these objects.