The Extra-Solar Planet Imager (ESPI): A Proposed MIDEX Mission

ESPI is a project that has been proposed as a NASA MIDEX for direct imaging and spectral analysis of giant planets orbiting solar-type stars. ESPI extends the concept suggested by Nisenson and Papaliolios (2001) for a square aperture apodized telescope that has sufficient dynamic range to directly detect exo-planets. ESPI can deliver high dynamic range imagery as close as 0.32 arcseconds to bright sources, permitting a sensitive search for exoplanets around nearby stars and a study of their characteristics in reflected light. It also permits unique observations of many Galactic, extragalactic and cosmological sources. The ESPI Survey will be conducted with a square 1.5 x 1.5-meter telescope mirror, operated in conjunction with a Jacquinot apodization mask that has a throughput of more than 30 percent. The system is capable of detecting Jupiter-like planets in relatively long-period orbits around as many as 160 to 175 stars with a signal-to-noise ratio greater than 5. In addition to the survey, ESPI will also study a few of the brightest discovered planets spectroscopically and spectrophotometrically to distinguish ice giants like Uranus and Neptune from gas giants like Jupiter and Saturn, and to determine whether super-Earth and super-Venus planets exist. Nisenson, P. and Papaliolios, C. 2001, ApJ, 548, L 201.