Planetary Systems Imager
The Planetary Systems Imager is an instrument for the Thirty Meter Telescope for the purpose of answering questions about the composition, formation, and history of planets around other stars. PSI is proposed as a second-generation instrument for TMT. It will also be able to make measurements of other kinds of objects, including in our own solar system. The questions motivating the types of measurements PSI will make is summarized here.
Block diagram of PSI wavefront sensing, control, and science backends.
The conceptual structure of the instrument in the above figure shows the path of light as it travels from the wavefront sensing and control systems to the backend science instruments. Light from the telescope enters a high-order common-path adaptive optics system, which corrects the light before it is sent to both 10-micron (PSI-10) and 2-5 micron (PSI-Red) backend instruments. Short-wavelength light is sent to PSI-Blue, where it undergoes additional wavefront correction with a visible-wavelength adaptive optics control loop before going on to visible-light instrumentation. Light from exoplanet atmospheres can also be characterized at high-resolution through fiber-fed spectroscopy in multiple wavelength regions.
The PSISIM simulation tool is being developed to support the development of the instrument and its subsequent surveys. It can simulate populations of planets with a distribution of spectral characteristics, simulate observing sequences and determine simulated survey results. It is developed in a modular format and has been used to aid the design of other instruments.
Mike Fitzgerald (mpfitz /at/ ucla.edu)