Abstract

Observational campaigns, concurrently with the discovery of exoplanets over the last two decades, have revealed a new mystery related to our own Solar system. Namely, observations of remnant icy bodies orbiting the Sun, beyond the orbit of Neptune, have unveiled an unexpected orbital behavior. As it turns out, these small bodies – known as trans-Neptunian objects – exhibit clustering in the orientation of their orbits. This peculiar spatial alignment has led to the so-called “Planet Nine” hypothesis that a yet undiscovered super-Earth resides in the distant Solar system and causes the observed clustering.

In this talk, I will briefly shed light on the observed signatures which promoted the aforementioned hypothesis and put forward an alternative. Specifically, I will demonstrate how a relatively massive disc of trans-Neptunian bodies can quench the quadrupolar torquing of the giant planets, and in the process orchestrate eccentric members of its population into the observed aligned state.