The Gemini Planet Imager: Integration and Test

ABSTRACT The Gemini Planet Imager is a next-gen eration instrument for the direct detection and characterization of young warm exoplanets, designed to be an order of magnitude more sensitive than existing facilities. It combines a 1700-actuator adaptive optics system, an apodized-pupil Lyot coronagraph, a precision interferometric infrared wavefront sensor, and a integral field spectrograph. All hardware and software subsystems are now complete and undergoing integration and test at UC Santa Cruz. We will present test results on each subsystem and the results of end-to-end testing. In laboratory testing, GPI has achieved a raw contrast (without post-processing) of 10 -6 5V at 0.4”, and with multiwavelength speckle suppression, 2x10 -7 at the same separation. Keywords: Adaptive optics; extrasolar planets; co ronagraphy; integral field spectrograph 1. INTRODUCTION Since 1995, the study of extrasolar planets has become one of the most active areas of astronomy. Precision Doppler measurements rapidly led to the discovery of dozens of planetary systems – all of them with architectures radically different than our own, dominated by giant planets much closer to their star than expected. Then, the first detections of transits opened up extrasolar planets to characterization – initially by providing measurements of mass and radius, and ultimately through measurements of planetary spectra in transit and eclipse. The Kepler spacecraft is now providing thousands of candidate and confirmed transiting planets and approaching the detection of Earth analogs. These impressive discoveries have left the theory of planet formation in some disarray, with no consensus model that explains all the properties of known systems. One unexplored piece of the puzzle is the frequency and properties of planets in the 5-40 AU regime, where the giant planets in our solar system reside and where giant planets are thought to form; a region almost inaccessible to Doppler and transit tec hniques. It is probed by gravitational microlensing but only in a broad statistical sense. Direct imaging with current-generation AO systems is most sensitive beyond 40 AU – it has led to a handful of significant discoveries