Dynamical Analysis of Three Distant Trans-Neptunian Objects with Similar Orbits

TL;DR

This study discovers and analyzes three distant trans-Neptunian objects with similar orbits, exploring their dynamical behavior and potential influences from hypothetical planets like Planet Nine.

Contribution

It reports the discovery of two new ETNOs with similar orbits to a known object and investigates their orbital stability and possible perturbations from unseen Solar System bodies.

Findings

ETNOs have semi-major axes around 172 AU and eccentricities near 0.77.

Their orbits remain close in the (a,e) phase space for about 100 million years.

Orbital dynamics are influenced by Neptune and possibly Planet Nine.

Abstract

This paper reports the discovery and orbital characterization of two extreme trans-Neptunian objects (ETNOs), 2016 QV$_{89}$ and 2016 QU$_{89}$, which have orbits that appear similar to that of a previously known object, 2013 UH$_{15}$. All three ETNOs have semi-major axes $a\approx 172$ AU and eccentricities $e\approx0.77$. The angular elements $(i,\omega,\Omega)$ vary by 6, 15, and 49 deg, respectively between the three objects. The two new objects add to the small number of TNOs currently known to have semi-major axes between 150 and 250 AU, and serve as an interesting dynamical laboratory to study the outer realm of our Solar System. Using a large ensemble of numerical integrations, we find that the orbits are expected to reside in close proximity in the $(a,e)$ phase plane for roughly 100 Myr before diffusing to more separated values. We then explore other scenarios that could influence their orbits. With aphelion distances over 300 AU, the orbits of these ETNOs extend far beyond the classical Kuiper Belt, and an order of magnitude beyond Neptune. As a result, their orbital dynamics can be affected by the proposed new Solar System member, referred to as Planet Nine in this work. With perihelion distances of 35-40 AU, these orbits are also influenced by resonant interactions with Neptune. A full assessment of any possible, new Solar System planets must thus take into account this emerging class of TNOs.