Detection of a Satellite of the Trojan Asteroid (3548) Eurybates -- A Lucy Mission Target

TL;DR

This paper reports the discovery of a satellite orbiting the Trojan asteroid (3548) Eurybates using Hubble Space Telescope images, which enhances the scientific potential of the Lucy mission.

Contribution

First detection of a satellite around Eurybates, providing new data for understanding Trojan asteroid systems and aiding Lucy mission planning.

Findings

Satellite diameter approximately 1.2 km

Projected separation between 1700-2300 km

Detection across three observation epochs

Abstract

We describe the discovery of a satellite of the Trojan asteroid (3548) Eurybates in images obtained with the Hubble Space Telescope. The satellite was detected on three separate epochs, two in September 2018 and one in January 2020. The satellite has a brightness in all three epochs consistent with an effective diameter of d2 =1.2+/-0.4 km. The projected separation from Eurybates was s~1700-2300 km and varied in position, consistent with a large range of possible orbits. Eurybates is a target of the Lucy Discovery mission and the early detection of a satellite provides an opportunity for a significant expansion of the scientific return from this encounter.