Discovery of a young subfamily of the (221)~Eos asteroid family

TL;DR

This paper reports the discovery of a young asteroid cluster, the (633)Zelima, formed from a breakup of an (221)Eos family member, with a statistically significant group of 26 members and an estimated age of about 2.9 million years.

Contribution

It identifies and characterizes a new young asteroid family using clustering and backward integration methods, revealing its age and stability.

Findings

Identified 26 members of the (633)Zelima asteroid cluster.

Estimated the cluster's age as approximately 2.9 million years.

Confirmed the cluster's statistical significance and orbital stability.

Abstract

In this work we report the discovery of a young cluster of asteroids that originated by the breakup of an asteroid member of the (221)Eos family. By applying the Hierarchical clustering method to the catalog of proper elements we have identified 26 members of this new small group of asteroids. We have established that the statistical significance of this cluster is $>99\%$, therefore it corresponds to a real asteroid family, named the (633)Zelima cluster, after its lowest numbered member. The orbits of its members are dynamically stable, a fact that enabled us to use the backward integration method, in two variants to identify potential interlopers and estimate its age. Applying it first on the orbits of the nominal family members we identified three asteroids as interlopers. Then we applied it on a set of statistically equivalent clones of each member to determine the age of the cluster, with a result of $2.9\pm0.2$Myrs.