# The Rafita asteroid family

## TL;DR

This paper introduces a new method to estimate the age of the Rafita asteroid family, characterized by asymmetry and leptokurtic inclination distribution, estimating it at approximately 490 million years with validation from independent dynamical models.

## Contribution

The study proposes a novel age estimation technique based on the asymmetry coefficient behavior, applicable to incomplete asteroid families like Rafita.

## Key findings

- Estimated Rafita family age: 490±200 Myr.
- Rafita family members can reach orbits similar to 8% of NEOs.
- Approximately 1% of simulated objects are in NEO space during the last 10 Myr.

## Abstract

The Rafita asteroid family is an S-type group located in the middle main belt, on the right side of the 3J:-1A mean-motion resonance. The proximity of this resonance to the family left side in semi-major axis caused many former family members to be lost. As a consequence, the family shape in the $(a,1/D)$ domain is quite asymmetrical, with a preponderance of objects on the right side of the distribution. The Rafita family is also characterized by a leptokurtic distribution in inclination, which allows the use of methods of family age estimation recently introduced for other leptokurtic families such as Astrid, Hansa, Gallia, and Barcelona. In this work we propose a new method based on the behavior of an asymmetry coefficient function of the distribution in the $(a,1/D)$ plane to date incomplete asteroid families such as Rafita. By monitoring the time behavior of this coefficient for asteroids simulating the initial conditions at the time of the family formation, we were able to estimate that the Rafita family should have an age of $490\pm200$ Myr, in good agreement with results from independent methods such as Monte Carlo simulations of Yarkovsky and Yorp dynamical induced evolution and the time behaviour of the kurtosis of the $\sin{(i)}$ distribution. Asteroids from the Rafita family can reach orbits similar to 8\% of the currently known near Earth objects. $\simeq$1\% of the simulated objects are present in NEO-space during the final 10 Myr of the simulation, and thus would be comparable to objects in the present-day NEO population.