COLLABORATIVE RESEARCH: Understanding Protoplanetary Disk Winds and Planet Interactions via Disk Emission Lines

Grant #: AST-1313003
Senior Scientist: Uma Gorti

Context: The late-stage evolution of protoplanetary disks as they form planets and eventually disperse is poorly understood. While it is recognized that viscous accretion, photoevaporation, and planet formation deplete disk mass in a few million years, the mass lost due to each process remains unquantified. High resolution spectra can provide valuable kinematic information and reveal signatures of accretion, photoevaporative winds, and planet-disk interactions. However, gas line emission is complex and difficult to interpret in the absence of detailed theoretical modeling.

Intellectual Merit: This collaborative research proposal will use an integrated approach that combines theory and observations to systematically study disk winds, evolution, and dispersal. We will analyze a unique dataset of high resolution optical and mid-infrared spectra for a sample of 55 disks around low and intermediate-mass stars at different stages of evolution. We will model the observed line emission fluxes and profiles using state-of-the-art thermochemical and 2-D hydrodynamical models for a sub-sample of disks, selected to represent various evolutionary epochs, to understand photoevaporative flows and to estimate resulting mass loss rates. Using hydrodynamical models to study the impact of planetary torques on disk structure, and thermochemical models to predict observable diagnostics, our study will distinguish rim emission due to photoevaporation from that due to planet-induced gaps and holes. This study will reveal the structure of the inner disk, calculate accretion rates, and probe emission characteristics when gas accretes past a planet. We will further seek new emission line diagnostics of photoevaporative winds and planet-disk interactions and make predictions for future observations using ALMA and other high resolution, high sensitivity facilities.

Broader Impacts: The proposed research will not only advance our understanding of how disks evolve and disperse, but will also promote the training of undergraduate and graduate students and the professional development of science and math teachers. All members of the team will be actively involved in public presentations to the broader community including local K-12 schools, various universities, conferences and other venues. Results from this project will be showcased in an episode of the SETI Institute radio show “Big Picture Science” and thus made accessible to the general public.