Beyond the Kuiper Belt Edge: New High Perihelion Trans-Neptunian Objects With Moderate Semi-major Axes and Eccentricities

TL;DR

This study reports the discovery of new high perihelion trans-Neptunian objects with moderate semi-major axes and eccentricities, providing insights into the outer solar system's structure and possible planetary influences.

Contribution

It presents the discovery and analysis of moderate orbit high perihelion objects, highlighting their potential origins via Neptune resonances and Kozai mechanisms, expanding understanding of outer solar system dynamics.

Findings

Several objects with high perihelia and moderate orbits were discovered.

Most objects are near Neptune mean motion resonances with significant inclinations.

Some objects' orbits suggest modification by Neptune's resonances and Kozai resonance mechanisms.

Abstract

We have been conducting a survey for distant solar system objects beyond the Kuiper Belt edge (~50 AU) with new wide-field cameras on the Subaru 8 meter and CTIO 4 meter telescopes. We are interested in the orbits of objects that are decoupled from the giant planet region in order to understand the structure of the outer solar system, including whether a massive planet exists beyond a few hundred AU as first reported by Trujillo and Sheppard (2014). In addition to discovering extreme trans-Neptunian objects detailed elsewhere, we have found several objects with high perihelia (q>40 AU) that differ from the extreme and inner Oort cloud objects due to their moderate semi-major axes (50<a<100 AU) and eccentricities (e<0.3). Newly discovered objects 2014 FZ71 and 2015 FJ345 have the third and fourth highest perihelia known after Sedna and 2012 VP113, yet their orbits are not nearly as eccentric or distant. We found several of these high perihelion but moderate orbit objects and observe that they are mostly near Neptune mean motion resonances and have significant inclinations (i>20 degrees). These moderate objects likely obtained their unusual orbits through combined interactions with Neptune's mean motion resonances and the Kozai resonance, similar to the origin scenarios for 2004 XR190. We also find the distant 2008 ST291 has likely been modified by the MMR+KR mechanism through the 6:1 Neptune resonance. We discuss these moderately eccentric, distant objects along with some other interesting low inclination outer classical belt objects like 2012 FH84 discovered in our ongoing survey.