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

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 caused by Ceres and Vesta. By extrapolating our results, we are able to constrain the global effect of close encounters with all 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.