Direct exoplanet imaging possibilities of the nulling stellar coronagraph

The nulling stellar coronagraph, first proposed by Roddier and Roddier and later demonstrated in a laboratory experiment is a technique to produce wide-field coronagraphic images. It uses a small phase-shifting mask in the focal plane to remove the central star by destructive interference. When applied to a space-based interferometric array of telescopes, it can be a powerful tool to search for faint companions around nearby stars or image circumstellar disks. A program was written to simulate the performance of a nulling stellar coronagraph for single or multi aperture telescopes in space or on the ground. In this study, we explore some aspects of the use of such a technique. By running our simulation program on various sources, we find that a nulling stellar coronagraph applied on a space interferometer like Darwin or TPF can image Earth-type planets in less than an hour of exposure time.