Study of ground-based infrared interferometer for observing extra-solar planets

Ground-based observation of 8-20 micron radiation from extra-solar earth-like planets has been proposed, using a pair of multi-element Linear Array or Fizeau interferometers as the photon collectors of a Michelson interferometer. A Linear Array might consist of afocal coronagraphs spanning some 100 meters. A parent star rejection factor of at least 500 is needed from a rotation or polarization shearing interferometer or a Bracewell null procedure (in addition to the rejection provided via the mirror array's Fraunhofer diffraction pattern). The design of an experiment to demonstrate feasibility of the instrument concept is described. Parent star rejection and atmospheric turbulence effects would be measured. Results from the test apparatus should show that a full-sized instrument could be a valuable contributor to the discovery and evaluation of extra-solar earth-like planets. This work was supported by Ruffner Associates, Inc.