A Fruit of a Different Kind: 2015 BP519 as an Outlier among the Extreme Trans-Neptunian Objects

TL;DR

This paper analyzes the orbital characteristics of the extreme trans-Neptunian object 2015 BP519, finding it to be a statistical outlier that challenges previous assumptions about ETNO distribution and the existence of a hidden massive planet.

Contribution

It provides evidence that 2015 BP519 does not follow the same dynamical pathways as other ETNOs, questioning its role as supporting evidence for a distant massive planet.

Findings

2015 BP519 is a statistical outlier among ETNOs.

Its orbital parameters differ significantly from other ETNOs.

It has the largest distance to its descending node among known ETNOs.

Abstract

A number of intriguing patterns have been identified in the distributions of the orbital elements of the known extreme trans-Neptunian objects or ETNOs --those with semimajor axis greater than 150 au and perihelion distance greater than 30 au. The announcement of the discovery of 2015 BP519, also known as Caju, has been hailed by some as a consistent piece of robust evidence for the existence of a yet-to-be-discovered massive planet far beyond the trans-Neptunian belt. In this Note, we use the latest data available to provide evidence against 2015 BP519 having followed the same dynamical pathway that placed other ETNOs where they are now. As an statistical outlier within the 29 known ETNOs, 2015 BP519 cannot be used as a reference to further support the trends perhaps present for other ETNOs. Asteroid 2015 BP519 represents a case of extreme dynamical anticorrelation within the ETNO orbital realm and the value of the distance to its descending node, nearly 700 au from the Sun, is the largest of any known ETNO.