Chaotic diffusion of the Vesta family induced by close encounters with massive asteroids

TL;DR

This study quantifies how close encounters with massive main belt asteroids cause chaotic orbital diffusion of Vesta family members, highlighting the dominant role of Ceres and Vesta for larger asteroids.

Contribution

It provides the first numerical estimate of semi-major axis diffusion due to close encounters with specific main belt asteroids, comparing this with the Yarkovsky effect.

Findings

Ceres and Vesta are the main contributors to orbital diffusion.

Close encounters dominate for asteroids larger than 40 km.

Results support the standard evolutionary scenario of the Vesta family.

Abstract

We numerically estimate the semi-major axis chaotic diffusion of the Vesta family asteroids induced by close encounters with 11 massive main belt asteroids : (1) Ceres, (2) Pallas, (3) Juno, (4) Vesta, (7) Iris, (10) Hygiea, (15) Eunomia, (19) Fortuna, (324) Bamberga, (532) Herculina, (704) Interamnia. We find that most of the diffusion is due to Ceres and Vesta. By extrapolating our results, we are able to constrain the global effect of close encounters with all the main belt asteroids. A comparison of this drift estimate with the one expected for the Yarkovsky effect shows that for asteroids whose diameter is larger than about 40 km, close encounters dominate the Yarkovsky effect. Overall, our findings confirm the standard scenario for the history of the Vesta family.