event
Wednesday 02 Nov 2011: Circular phase mask coronagraphy for high contrast imaging of exoplanets
Dr Mamadou N'Diaye - L'Observatoire Astronomique Marseille-Provence
Physics, 4th floor 14:00-14:45
Direct imaging and spectroscopy of exoplanets in the visible and near-infrared bands rise many expectations in the astronomical community due to the clues they will provide on topics such as planet frequency, planet diversity or formation and evolution of planetary systems. However, these observations are limited by the very high flux ratio (10^5 to 10^10) at a small angular distance (less than 1 arcsec) between a star and its planetary companions. High contrast imaging techniques, combining extreme adaptive optics, stellar coronagraphy and post processing methods, are required to disentangle the photons of the host star and its planetary companions.
My presentation will be focused here on coronagraphy with a brief review the main concepts. I will focus on those using circular phase masks since these promising devices offer a very small inner working angle (less than 2lambda/D), useful for the observation of the closest companions to their host star. I will expose our last improvements and show laboratory results.
