The Pan-STARRS 1 Discoveries of five new Neptune Trojans

TL;DR

This paper reports the discovery of seven Neptune Trojans via the Pan-STARRS 1 survey, with four likely primordial and one recent capture, providing insights into their stability and population characteristics.

Contribution

The study presents five new Neptune Trojans discovered by Pan-STARRS 1, analyzes their orbital stability, and estimates the inclination distribution of the Neptune Trojan population.

Findings

Four L4 Trojans are stable for over 1 Gyr, indicating primordial origin.

One L5 Trojan is only stable for a few million years, suggesting recent capture.

The inclination width of the Neptune Trojan population is estimated to be between 7° and 27°.

Abstract

In this work we report the detection of seven Neptune Trojans (NTs) in the Pan-STARRS 1 (PS1) survey. Five of these are new discoveries, consisting of four L4 Trojans and one L5 Trojan. Our orbital simulations show that the L5 Trojan stably librates for only several million years. This suggests that the L5 Trojan must be of recent capture origin. On the other hand, all four new L4 Trojans stably occupy the 1:1 resonance with Neptune for more than 1 Gyr. They can, therefore, be of primordial origin. Our survey simulation results show that the inclination width of the Neptune Trojan population should be between $7^{\circ}$ and $27^{\circ}$ at $>$ 95% confidence, and most likely $\sim 11^{\circ}$. In this paper, we describe the PS1 survey, the Outer Solar System pipeline, the confirming observations, and the orbital/physical properties of the new Neptune Trojans.