paired: A Statistical Framework for Determining Stellar Binarity with Gaia RVs. I. Planet Hosting Binaries

The effect of stellar multiplicity on the formation and evolution of planetary systems is complex. At a demographic level, campaigns with both high-resolution imaging and radial velocity observations indicate that planet formation is strongly disrupted by close binaries, while being relatively unaffected by wide companions. However, the magnitude and distance-limited nature of those tools mean that large ranges of mass ratios and separations remain largely unexplored. The Early Data Release 3 (EDR3) from the <em>Gaia</em> Mission includes radial velocity measurements of over 6.5 million targets, which we employ to explore the effect of binary companions within a statistical framework called <strong>paired.</strong> These companions present as a source of excess radial velocity noise in the <em>Gaia</em> catalog, when compared to the typical noise for stars of similar spectral type and magnitude. Within this framework, we examine the evidence for stellar multiplicity among the stars surveyed by NASA's <em>Kepler</em> and <em>TESS</em> missions. We use radial velocity errors published in <em>Gaia</em> EDR3 to estimate the probability of an unresolved stellar companion for a large subset of the <em>Kepler </em>and <em>TESS</em> Input Catalog stars, where possible benchmarking our inferred radial velocity semi-amplitudes against the those from ground-based radial velocity surveys. We determine that we are typically sensitive out to several AU and mass ratios &gt;0.1, dependent upon the stellar magnitude. We aim for <strong>paired</strong> to be a useful community tool for the exploration of the effects of binarity on planets at a population level, and for efficient identification of false-positive transit candidates.