Portrait of Theobalda as a Young Asteroid Family

TL;DR

This study characterizes the Theobalda asteroid family, identifying its members, chaotic orbital dynamics, and estimating its age at approximately 6.9 million years, highlighting its significance in asteroid family evolution.

Contribution

It provides the first detailed analysis of the Theobalda asteroid family, including its origin, chaotic orbital behavior, and age estimation, using new clustering and chronologic methods.

Findings

The family has 128 members identified via hierarchical clustering.

Most members are on chaotic orbits due to resonances.

The family is approximately 6.9 million years old.

Abstract

The (778) Theobalda asteroid family attracted little attention so far, but our study shows that it is important in several aspects. In this paper we investigate the origin and evolution of Theobalda family. Firstly, we identify the family as a statistically relevant group in the space of synthetic proper elements. Using the hierarchical clustering method and adopted cut-off velocity of d_{cutoff}=85 m/s we found that Theobalda family currently consists of 128 members. This family is located in the outer belt, near proper semi-major axis a_{p}~3.175 au. This region is crossed by several three-body mean motion resonances which give rise to significant chaotic zones. Consequently, the majority of family members reside on chaotic orbits. Using two independent methods, chaotic chronology and backward integration, we found Theobalda family to be only 6.9 +/- 2.3 Myr old. We have also estimated, that the family was likely produced by the cratering impact on a parent body of diameter D_{PB}~78 +/- 9 km.