Abstract
The top priority recommendation from the Astro2020 Decadal Survey was a large IR/O/UV space telescope capable of directly imaging about 25 Earth-like planets in the habitable zones of Sun-like stars to probe their atmospheres for signs of life. Thus, NASA is beginning the process of designing the Habitable Worlds Observatory (HWO), and a list of the 164 best targets for HWO has been released to the community for precursor science (Mamajek & Stapelfeldt 2023). A crucial question to answer is whether these targets possess companions (stars, brown dwarfs, or giant planets) which may preclude the existence of Earth-sized planets in the habitable zone. To reveal the presence of companions on solar-system scales, astrometry data can be combined between past and current surveys, namely Hipparcos and Gaia, which allows long-term accelerations to be calculated. Here, I will present the results of cross-matching the HWO provisional target list with the Hipparcos-Gaia Catalog of Accelerations (Brandt 2021) to search for targets with significant astrometric accelerations. I will introduce constraints on mass and separation of companions around accelerating and non-accelerating targets using an analytical modeling framework adapted from Kervella et al. (2019, 2022). Finally, I will discuss future steps to constrain companions in these systems using similar and complementary methods.
