Multi-StarWavefront Control: Science Case and Technological Prospects with High-Contrast Imaging of Exoplanets in Multi-Star Systems for Roman and HWO

Binary and other multi-star systems pose an additional challenge for starlight suppression systems due to the combined stellar components’ diffraction and aberration leakage into the region of interest. As a result, many multi-star systems are considered unsuitable for direct imaging by the Habitable worlds Observatory (HWO). Multi-Star Wavefront Control (MSWC) is a method that uses the deformable mirror (DM) on a coronagraph instrument to directly image planets and disks in multi-star systems such as Alpha Centauri. MSWC can thus enable missions such as the Roman Space Telescope and HWO to handle binary targets. Imaging planets around multi-star systems enables exciting science, in part because about half of Sun-like stars have stellar companions, and in part because multi-star systems differ from single stars in terms of planet formation, dynamics, and demographics. MSWC is a “contributed mode” on the Roman Space Telescope Coronagraph Instrument, and is compatible with HWO. We review the prospects and science case for exoplanets around binaries using Roman and HWO coronagraphs, and the results of the technology development for MSWC obtained on the Occulting mask coronagraph (OMC) in JPL’s High Contrast Imaging Testbed (HCIT) representative of the Roman coronagraph instrument. These experiments used a binary star source representative of the Alpha Centauri stars and demonstrated 2.1e-8 contrast for planets around the A component and 1.8e-7 for planets around the B in Band-3d. These contrast levels are consistent with potential detection in reflected light of the planet candidate identified with NEAR and JWST. Further contrast improvements are expected in planned future tests, including those with configurations relevant for HWO that will require deeper contrast levels.