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 Gaia 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 paired. These companions present as a source of excess radial velocity noise in the Gaia 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 Kepler and TESS missions. We use radial velocity errors published in Gaia EDR3 to estimate the probability of an unresolved stellar companion for a large subset of the Kepler and TESS 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 >0.1, dependent upon the stellar magnitude. We aim for paired 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