The Planetary Systems Imager for TMT: driving science cases and top level requirements

The Planetary Systems Imager (PSI) is a second-generation exoplanet detection and characterization instrument concept for the Thirty Meter Telescope (TMT). PSI will enable extreme adaptive optics imaging and spectroscopy from the visible into the infrared. Its high contrast, coupled with TMT's sensitivity, will access entirely new regions of exoplanet parameter space. Here we describe the driving exoplanet science cases for PSI, including detecting and characterizing rocky planets around nearby M dwarfs, constraining atmospheric and surface compositions and variability, measuring accretion onto protoplanets on Solar System orbital scales, and more. We present the top level instrument requirements for each subsystem, which we derive from these science cases and inform using simulations. We discuss PSI's expected science outcomes for exoplanet studies, and also highlight examples of its potential for Solar System, galactic, and extragalactic science.