Program: GN-2020A-Q-219

Most stars form with a binary companion, and while binaries can potentially create hostile environments for planets, at least some planets form/survive even in very close, dynamically active binaries. The demographics of binaries among planet hosts offer crucial context for the evolution of planets hosted by binary systems, as different hurdles to formation/survival leave different imprints. These imprints are crucial for understanding the systematic effects of binarity on on eta-Earth, for estimating the likelihood of detectable Earth analogs among the nearest systems (i.e., Alpha Cen), and for removing the biases in transit-based radii. Gaia offers a new opportunity to identify likely binaries, which show excess noise in their astrometric fit. However, it only conveys (non)existence and not the separation/contrast. We are pursuing a multi-stage program to efficiently survey all Kepler Objects of Interest for binary companions, obtaining increasing spatial resolution until a companion is resolved. We have identified 46 KOIs that are likely to have companions from Gaia excess noise, but were not resolved when observed with smaller telescopes (i.e., WIYN/NESSI). These are the final ~5% of our sample that must be observed on the largest telescopes to resolve the companions, and since they are the tightest, they are most promising for probing the impact of binary companions on planets and for measuring orbital arcs that indicate system dynamics. Given the astrophysical and observational impacts of binary companions on planetary systems and their discovery, our sample will also provide lasting legacy value for the Kepler planetary sample and its interpretation.