A spectral comparison of (379) Huenna and its satellite

TL;DR

This study presents near-infrared spectral measurements of asteroid (379) Huenna and its satellite, introducing a method to extract the satellite's spectrum despite limited resolution, revealing their C-type characteristics.

Contribution

A novel spectral separation method for unresolved asteroid satellites, demonstrated on (379) Huenna and its dimmer companion, enabling compositional analysis.

Findings

Huenna has a broad, shallow 1 μm feature and low slope, typical of C-type asteroids.

The satellite's spectrum is consistent with C- or X-complex classification.

Data quality limited detection of subtle spectral features in the satellite.

Abstract

We present near-infrared spectral measurements of Themis family asteroid (379) Huenna (D~98 km) and its 6 km satellite using SpeX on the NASA IRTF. The companion was farther than 1.5" from the primary at the time of observations and was approximately 5 magnitudes dimmer. We describe a method for separating and extracting the signal of a companion asteroid when the signal is not entirely resolved from the primary. The spectrum of (379) Huenna has a broad, shallow feature near 1 {\mu}m and a low slope, characteristic of C-type asteroids. The secondary's spectrum is consistent with the taxonomic classification of C-complex or X-complex. The quality of the data was not sufficient to identify any subtle feature in the secondary's spectrum.