Binary stripping as a plausible origin of correlated pairs of extreme trans-Neptunian objects

Abstract

Asteroids that follow similar orbits may have a dynamical connection as their current paths could be the result of a past interaction with a massive perturber. The pair of extreme trans-Neptunian objects or ETNOs (474640) 2004 VN 112 -2013 RF 98 exhibits peculiar relative orbital properties, including a difference in longitude of the ascending node of just 1.• 61 and 3.• 99 in inclination. In addition, their reflectance spectra are similar in the visible portion of the spectrum. The origin of these similarities remains unclear. Neglecting observational bias, viable scenarios that could explain this level of coincidence include fragmentation and binary dissociation. Here, we present results of extensive direct N -body simulations of close encounters between wide binary ETNOs and one transPlutonian planet. We find that wide binary ETNOs can dissociate during such interactions and the relative orbital properties of the resulting unbound couples match reasonably well those of several pairs of known ETNOs, including 474640-2013 RF 98 . The possible presence of former binaries among the known ETNOs has strong implications for the interpretation of the observed anisotropies in the distributions of the directions of their orbital poles and perihelia.