New multi-part collisional model of the Main Belt: The contribution to Near-Earth Asteroids

ZAIN, P. S.; DE ELÍA, G. C.; DI SISTO, R. P.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2020 vol. 639 p. 1 - 13

0004-6361

Aims. We developed a six-part collisional evolution model of the Main Asteroid Belt (MB) and used it to study the contribution of the different regions of the MB to the Near-Earth Asteroids (NEAs).Methods. We built a statistical code called ACDC that simulates the collisional evolution of the MB, split in six regions (namely Inner,Middle, Pristine, Outer, Cybele and High-Inclination belts), according to the positions of the major resonances present there (ν6 , 3:1J,5:2J, 7:3J and 2:1J). We consider the Yarkovsky effect and the mentioned resonances as the main mechanism that removes asteroidsfrom the different regions of the MB and delivers them to the NEA region. We then calculate the evolution of the NEAs coming from the different source regions by considering the bodies delivered by the resonances and mean dynamical time-scales in the NEA population.Results. Our model is in agreement with the major observational constraints associated with the MB, such as the size distributionsof the different regions of the MB, and the number of large asteroid families. It is also able to reproduce the observed NEAs with H < 16 and agrees with recent estimations for H < 20, but deviates for smaller sizes. We find that most sources make a significantcontribution to the NEAs, however the Inner and Middle belt stands out as the more important source of NEAs, followed by the Outerbelt. The contributions of the Pristine and Cybele regions are minor. The High-Inclination belt is the source of only a fraction of theactual observed NEAs with high inclination, as there are dynamical processes in that enable asteroids to increase and decrease theirinclinations.