Extreme AO Observations of Two Triple Asteroid Systems with SPHERE

TL;DR

This study reports the discovery of a new moonlet around asteroid Elektra using SPHERE/VLT, providing insights into the formation and spectral properties of triple asteroid systems through high-resolution imaging and spectroscopy.

Contribution

The paper presents the first detection of a second moonlet around Elektra and compares spectral data of satellites and primaries in two triple asteroid systems.

Findings

New moonlet S/2014 (130) 1 discovered around Elektra

No significant spectral differences between satellites and primaries

Moonlets likely formed by sub-disruptive impacts

Abstract

We present the discovery of a new satellite of asteroid (130) Elektra - S/2014 (130) 1 - in differential imaging and in integral field spectroscopy data over multiple epochs obtained with SPHERE/VLT. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. We find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.