Toward a binary probability for every known exoplanet host star: a statistical framework with Gaia

The effect of stellar multiplicity on planet formation is complex, and can range from complete suppression of planets at one extreme, to negligible impact at the other. Campaigns with both high-resolution imaging and radial velocity observations indicate that planet formation can be strongly disrupted by close binaries while being relatively unaffected by wide companions. The magnitude and distance-limited nature of those tools mean that large swaths of companion parameter space (mass ratio and separation) remain largely unexplored in our best planet sample, the KeplerGaia Mission includes RV measurements of over 6 million targets that can be used to explore the effect of binary companions within a statistical framework. Many of these stars are members of unresolved multiple star systems, presenting as a source of excess radial velocity noise in the Gaia catalog. We employ these published EDR3 RV error estimates to extract the probability of an unresolved stellar companion for Kepler planet host stars, typically sensitive out to several AU and mass ratios >0.1.