The Demographics of Planet Survival in Binary Star Systems

The majority of Sun-like stars form with a binary companion, and those binary systems appear to be hostile sites for planet formation and survival. When a binary companion is found on solar-system scales, the planet occurrence is suppressed by a factor of ∼3, but nonetheless even some very dynamically active binary systems do host surviving planets. The impact of wide or low-mass binary companions appears to be less severe, but has not been fully quantified due to small survey samples and biases in both the Kepler target selection and the binary census. The dependence of planet survival on semi-major axis and on companion mass will distinguish which processes are most important in either forestalling planet formation (via disk dispersal and planetesimal stirring) or destroying planets after they form (via secular orbital evolution). I will present a multiplicity census of the full Kepler planet-host population (~3000 planet hosts), combined with an updated model of the biases for and against binary stars in the Kepler target selection. This survey expands past statistical samples by an order of magnitude, allowing for a detailed assessment of which binary features correlate with planet destruction/survival. These planet-hosting systems also establish the basis for followup programs studying the importance of orbital parameters such as mutual-inclination and eccentricity (via multi-epoch followup) and whether planet occurrence continues to evolve over Gyr timescales (using gyrochronological ages).