# Asteroid 2014 YX49: a large transient Trojan of Uranus

## TL;DR

This paper reports the discovery and analysis of a second transient Uranian Trojan asteroid, 2014 YX49, highlighting its orbital characteristics, stability, and the dynamical mechanisms involved in its capture and ejection.

## Contribution

It presents the identification and detailed dynamical analysis of a new transient Uranian Trojan, expanding knowledge of small body populations in the outer Solar system.

## Key findings

- 2014 YX49 is a transient L4 Trojan of Uranus with higher inclination and larger size than the first known Uranian Trojan.
- It may remain co-orbital with Uranus for nearly 1 million years, with stability influenced by Jupiter and Neptune.
- The capture and ejection involve ephemeral multibody mean motion resonances.

## Abstract

In the outer Solar system, primordial Trojan asteroids may have remained dynamically stable for billions of years. Several thousands of them accompany Jupiter in its journey around the Sun and a similarly large population may be hosted by Neptune. In addition, recently captured or transient Jovian and Neptunian Trojans are not uncommon. In contrast, no Trojans of Saturn have been found yet and just one Uranian Trojan is known, 2011 QF99. Here, we discuss the identification of a second Trojan of Uranus: 2014 YX49. Like 2011 QF99, 2014 YX49 is a transient L4 Trojan although it orbits at higher inclination (25.55 degrees versus 10.83 degrees), is larger (absolute magnitude of 8.5 versus 9.7) and its libration period is slightly shorter (5.1 versus 5.9 kyr); contrary to 2011 QF99, its discovery was not the result of a targeted survey. It is less stable than 2011 QF99; our extensive N-body simulations show that 2014 YX49 may have been following a tadpole trajectory ahead of Uranus for about 60 kyr and it can continue doing so for another 80 kyr. Our analysis suggests that it may remain as co-orbital for nearly 1 Myr. As in the case of 2011 QF99, the long-term stability of 2014 YX49 is controlled by Jupiter and Neptune, but it is currently trapped in the 7:20 mean motion resonance with Saturn. Consistently, the dynamical mechanism leading to the capture into and the ejection from the Trojan state involves ephemeral multibody mean motion resonances.