In their research note, the authors describe the permanent capture of an ISO this way: “The permanent capture of a small body, P, about the Sun, S, from interstellar space occurs when P can never escape back into interstellar space and remains captured within the Solar System for all future time, moving without collision with the Sun.”
Our Solar System’s phase space has capture points where an ISO can find itself gravitationally bound to the Sun.
Phase space is a mathematical representation that describes the state of a dynamical system like our Solar System.
The upcoming Vera Rubin Observatory is expected to discover many more ISOs.
The paper focuses on the theoretical nature of phase space and ISO capture.
The researchers identified openings in the Solar System’s phase space that could allow some of these objects, or ISOs or rogue planets, to reach permanent weak capture.
Every million years, about two of our stellar neighbours come within a few light years of Earth.
There’s not much debate that rogue planets exist likely in large numbers.
The Oort Cloud’s outer boundary is about 1.5 light years away, so some of these stellar encounters could easily dislodge objects from the cloud and send them toward the inner Solar System.
Permanent capture points are regions in space where an object can be permanently captured into a stable orbit.