Published online by Cambridge University Press: 11 October 2004
MIRI, the mid-IR instrument of JWST (James Webb Space Telescope),will include a coronagraphic device for which the ultimate goal isthe detection and caracterization of extrasolar planets aroundnearby stars. In this paper, we describe the optical concept ofMIRI and the instrumental choices that were made in phase A and Bregarding the coronagraphic system. Finally, we will presentnumerical simulations that we carried out to evaluate thecapability for detecting extrasolar giant gazeous planets.