Close Encounters of Wide Binaries Induced by the Galactic Tide: Implications for Stellar Mergers and Gravitational-Wave Sources

Understand

A substantial fraction of stars can be found in wide binaries with projected separations between $\sim10^2$ and $10^5\,\rm AU$.

• In the standard lore of binary physics, these would evolve as effectively single stars that remotely orbit one another on stationary Keplerian ellipses.
• However, embedded in their Galactic environment their low binding energy makes them exceptionally prone to perturbations from the gravitational potential of the Milky Way and encounters with passing stars.
• Employing a fully relativistic $N$-body integration scheme, we study the impact of these perturbations on the orbital evolution of wide binaries along their trajectory through the Milky Way.