Simulating the effects of exozodiacal dust in WFIRST CGI observations

Abstract

The WFIRST Coronagraph Instrument (CGI) will image the environment close to stars at orders of magnitude higher sensitivity than current observatories. In addition to directly imaging giant exoplanets, WFIRST CGI has unprecedented sensitivity to scattered light from circumstellar dust. Most modeling has been confined to the dark-hole regime of the coronagraph (approximately 0.15 arcsec to 1 arcsec). This work uses publicly available field-dependent point spread functions to model an exozodiacal disk within the 0.15 arcsec inner working angle. For this simple Solar System-like test case, we find an approximately 25% increase in the transmitted exozodiacal flux due to light inside the inner working angle. We also describe plans to accelerate and extend this modeling to a wider range of geometries, and to quantify the impact on post-processing and source detection.