# The olivine-dominated composition of the Eureka family of Mars Trojan asteroids

## TL;DR

This study used spectroscopic and photometric observations to confirm that two Mars Trojan asteroids in the Eureka family are olivine-dominated, suggesting a common origin and composition for the family.

## Contribution

It provides the first detailed spectral analysis confirming the olivine-dominated composition of Eureka family asteroids, supporting a shared origin hypothesis.

## Key findings

- Eureka family asteroids are olivine-dominated (A, Sa types).
- Spectroscopic data supports a common origin for the family.
- Results have implications for the origin of Mars Trojans.

## Abstract

We have used the XSHOOTER echelle spectrograph on the European Southern Obseratory (ESO) Very Large Telescope (VLT) to obtain UVB-VIS-NIR (ultraviolet-blue (UVB), visible (VIS) and near-infrared (NIR)) reflectance spectra of two members of the Eureka family of L5 Mars Trojans, in order to test a genetic relationship to Eureka. In addition to obtaining spectra, we also carried out VRI photometry of one of the VLT targets using the 2-m telescope at the Bulgarian National Astronomical Observatory - Rozhen and the two-channel focal reducer. We found that these asteroids belong to the olivine-dominated A, or Sa, taxonomic class. As Eureka itself is also an olivine-dominated asteroid, it is likely that all family asteroids share a common origin and composition. We discuss the significance of these results in terms of the origin of the martian Trojan population.