ExoPTF Whitepaper Coronagraphic Detection of Exosolar Planets with JWST

2. JWST Instrument Complement JWST is not primarily designed to conduct coronagraphic observations. It’s segmented mirror telescope architecture, as shown in Figure 1, generates considerable additional diffraction structure in the telescope’s point spread function compared to that of a monolithic mirror. The JWST project has set a performance requirement of diffraction limited imaging at 2 μm. This is defined in terms of an allocation of 150 nm wavefront error at the NIRCam focal plane. This 150 nm allocation contains specific reserves, and the degree to which these reserves are utilized or re-allocated is likely to influence the final performance for high contrast imaging. However, the stability, freedom from atmospheric absorptions, and low infrared backgrounds for JWST in space offer unique advantages that make possible a range of applications that complement other approaches. JWST has a unique discovery space for imaging the thermal emission of Jovian planets because of its superb sensitivity at the wavelengths where this emission emerges.