Physical and dynamical characterization of the Euphrosyne asteroid Family

TL;DR

This study combines spectroscopic observations and dynamical simulations to characterize the physical and orbital properties of the Euphrosyne asteroid family, revealing its homogeneous composition, collisional origin, and a revised age estimate of approximately 280 million years.

Contribution

It provides a comprehensive analysis of the Euphrosyne family using spectroscopy and simulations, offering new insights into its formation, composition, and age.

Findings

Family members have homogeneous composition.

Formed via reaccumulation, not cratering.

Age estimated at 280 Myr, younger than previous estimates.

Abstract

The Euphrosyne asteroid family occupies a unique zone in orbital element space around 3.15 au and may be an important source of the low-albedo near-Earth objects. The parent body of this family may have been one of the planetesimals that delivered water and organic materials onto the growing terrestrial planets. We aim to characterize the compositional properties as well as the dynamical properties of the family. We performed a systematic study to characterize the physical properties of the Euphrosyne family members via low-resolution spectroscopy using the IRTF telescope. In addition, we performed smoothed-particle hydrodynamics (SPH) simulations and N-body simulations to investigate the collisional origin, determine a realistic velocity field, study the orbital evolution, and constrain the age of the Euphrosyne family. Our spectroscopy survey shows that the family members exhibit a tight taxonomic distribution, suggesting a homogeneous composition of the parent body. Our SPH simulations are consistent with the Euphrosyne family having formed via a reaccumulation process instead of a cratering event. Finally, our N-body simulations indicate that the age of the family is 280 Myr +180/-80 Myr, which is younger than a previous estimate.