Growing Pains: Binaries Suppress Planetary Systems at a Young Age

Abstract Planet-hosting stars in the Kepler field have been shown to disfavor a close ( ρ < 50 au) stellar companion compared to field binary rates, suggesting a suppression of the occurrence of planets by close binaries. I analyzed 78 young (<500 Myr), transiting planetary systems for stellar multiplicity to determine if this suppression is still seen at young ages. Based on Gaia common proper motion, RUWE values, and a literature review, I found 21 planet-hosting stars to be in binary systems, with 4 being closely separated. This close binary rate (5.1% ± 3.4%) is less than the field binary rate (15.2% ± 2.0%), suggesting that the suppression of planetary systems by binaries must occur at very early ages, which is consistent with rapid disk dissipation and dynamic instability models.