Technology and Science Advancing Observations with Roman Coronagraph Informed by Ground-Based High-Contrast Imaging

The Roman Coronagraph technology demonstration aims to achieve contrasts below 10^-7 within its dark hole and to prove the ability to detect and characterize faint companions around bright stars. This study, informed by the ongoing OASIS survey at Subaru Telescope and precursor survey work, evaluates potential targets for the demonstration phase.

OASIS provides at least three compelling targets: the brown dwarf HIP 71618 B and the superjovian planets HIP 54515 b and HIP 99770 b. HIP 71618 is especially well suited for demonstrating the coronagraph's core performance requirement, while all three are good candidates for spectroscopic mode observations. Each target can be paired with a vetted PSF reference star. HIP 71618 and HIP 54515 are already planned for technology demonstration observations, but the study argues for the added programmatic and scientific value of including spectroscopic observations of HIP 99770 as well.