Numerical modeling of the Habex coronagraph

Abstract

The Habex study, commissioned by NASA in preparation for the 2020 Decadal Survey, is evaluating a 4 meter space telescope for high contrast imaging and spectral characterization of extrasolar terrestrial planets. Its off-axis configuration, active structural metrology, and low-disturbance pointing control provide an optimal system for coronagraphs. We present predictions of the Habex performance using a charge 6 vortex coronagraph that have been obtained using numerical modeling techniques developed for the WFIRST coronagraph. The models include realistic optical surface and polarization-induced aberrations, pointing jitter, and thermally-induced wavefront variations. Wavefront control using dual deformable mirrors is simulated to create a dark, high-contrast hole around the star. The results show that current technologies can closely approach the Habex performance goals, and with some additional development in key areas (e.g., deformable mirror surface quality, low-polarization coatings, etc.) over the next few years they should reliably meet them.