Close Trans-Neptunian Object Passages as a Driver of the Origin and Evolution of Ultrawide Kuiper Belt Binaries

Within the dynamically cold low inclination portion of Classical Kuiper Belt, there exists a population weakly bound binary systems with number unusual properties; most notable which is their extremely wide orbital separations; beyond 7% Hill radii. The stability and evolution these Ultra-Wide Trans-Neptunian Binaries (TNBs) have, in past, been studied extensively under assumption that primary evolving mechanisms are interactions between components impacting Objects (TNOs). Here, we instead study as driven by gravitational perturbations close passing but non-impacting TNOs. By simulating passages, show aggregate effects encounters over billions years have significant effect on Belt evolution. Such processes can lead to tight binaries widening significantly time, approaching sometimes surpassing separation widest known TNBs. We also find eccentricity distributions observed TNBs be sampled from such widened binaries. While unable produce enough explain abundance, properties ones do consistent