Opportunities for Imaging the Planet Forming Environment with ALMA

In recent years, spatially resolved observations of protoplanetary disks have delivered stunning images of radial substructures and azimuthal asymmetries, yielding new insights into the planet-forming environment. With its additional capability to spectrally resolve molecular line emission, the Atacama Large Millimeter Array (ALMA) is providing an exciting new dimension with which to study protoplanetary disk dynamics, structures, and astrochemical inventories. In the first part of this talk, we will describe how we use the bulk Keplerian motion of protoplanetary disks to precisely (<5%) constrain the central stellar mass, and, when combined with stellar orbits, how these constraints can unlock the architectures of multiple-star protoplanetary systems. We will discuss our survey of 20 circumbinary systems in the context of the dozen Kepler circumbinary (or "Tatooine") planets, its implications for a coplanar planet/disk population around short-period binaries (periods < 40 days), and the possibility of a set of widely dispersed orbits around wider binary systems (periods > months). Next, we will describe how our advances in Hamiltonian Monte Carlo techniques for high dimensional Bayesian inference (as is necessary for multi-instrument orbital datasets) have enabled us to infer the architecture of the nearby, triple mid-M dwarf system TWA 3, whose circumbinary protoplanetary disk lies in a "transition region" between the coplanar and dispersed populations. In the final section of the talk, I will highlight the upcoming results from the Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program ("The Chemistry of Planet Formation") and identify opportunities to use molecular emission to search for (proto)-planetary kinematic signatures. Central to these efforts are robust, non-parametric imaging methodologies, broadly categorized under the umbrella of "Regularized Maximum Likelihood" (RML) techniques. We will conclude with preliminary results from our open-source "Million Points of Light" RML framework and sketch out potential high-fidelity imaging workflows for ALMA continuum and spectral line datasets.