Extra-solar planetary imager (ESPI) for space-based Jovian planetary detection

Abstract

The Extra-Solar Planetary Imager (ESPI) is envisioned as a space based, high dynamic range, visible imager capable of detecting Jovian like planets. Initially proposed as a NASA Midex (NASA/Medium Class Explorer) mission (PI:Gary Melnick), as a space-based 1.5 x 1.5 m 2 Jacquinot apodized square aperture telescope. The combination of apodization and a square aperture telescope reduces the diffracted light from a bright central source increasing the planetary to stellar contrast over much of the telescope focal plane. As a result, observations of very faint astronomical objects next to bright sources with angular separations as small as 0.32 arcseconds become possible. This permits a sensitive search for exo-planets in reflected light. ESPI is capable of detecting a Jupiter-like planet in a relatively long-period orbit around as many as 160 to 175 stars with a signal-to-noise ratio > 5 in observations lasting maximally 100 hours per star out to ~16 parsecs. We discuss the scientific ramifications, an overview of the system design including apodizing a square aperture, signal to noise issues and the effect of wavefront errors and the scalability of ESPI with respect to NASA s Terrestrial Planet Finder mission.

Rounding up the wanderers: optimizing coronagraphic searches for extrasolar planets

“…With the analytic relations derived in the previous sections in hand, I can now compare various proposed coronagraphic planet imaging satellites. A survey of the SPIE conference proceedings "Future EUV/UV and Visible Space Astrophysics Missions and Instrumentation" and "High-Contrast Imaging for Exo-Planet Detection" turns up at least six planned coronagraphic satellites: EPIC/OPD (Mennesson et al 2003), ECLIPSE (Trauger et al 2003;Hull et al 2003), TPF-C (Brown et al 2003;Traub & et al 2006), ESPI (Lyon et al 2003), UMBRAS (Schultz & et al 2003), ExPO (Gezari et al 2003), and TOPS (Guyon & et al 2006). For comparison, I also include the Hubble Space Telescope (Brown & Burrows 1990) and the Hubble Space Telescope with a corrective secondary mirror, HST * as proposed by Malbet et al (1995).…”