eXtreme Adaptive Optics Planet Imager

Simulated XAOPI image. This shows a 15-minute exposure of a solar-type star at a distance of 10 pc (located behind an occulting spot). Visible in the image is an 8 Jupiter-mass planet (circled) at a distance of 6 AU from the primary.

Direct detection of extrasolar planets

Current radial-velocity searches for extrasolar planets, though powerful, are fundamentally constrained in the range of orbits they can access by the need for a near-complete orbital period: the largest detectable semi-major axis only grows with time to the 2/3 power. In our professional lifetimes, radial velocity detection will barely reach planets with orbits comparable to Saturn. To probe the 5-100 AU range different techniques are needed. Direct detection of photons emitted by extrasolar planets is one such technique, but requires contrast levels of 10⁷-10⁹ at near-infrared wavelengths. We have designed an adaptive optics (AO) system capable of reaching these contrasts.

XAOPI, the eXtreme Adaptive Optics Planet Imager, is a 4096-actuator AO system. It will achieve Strehl ratios >0.9, and is optimized to remove scattered light from 0.2-1 arcseconds. Simulations predict that it will achieve contrast levels of 10⁷-10⁸ around for target stars with R<7. This allows detection of near-IR emission from warm extrasolar planets younger and/or more massive than Jupiter around a significant sample of target stars.

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Graphical Version

Center for Adaptive Optics