We study the dynamical and collisional evolution of Near-Earth asteroids (NEAs) in main belt–crossing orbits (NEACs). We selected NEACs with H2. 5 au). We computed the fraction of each orbit spent within the main belt (MB), dynamical occupancy maps in the (a, e) plane, and median lifetimes. Using collisional evolution, we obtained size-dependent timescales and the change in the NEA size-frequency distribution (SFD) over 1 Myr, along with the impactor and crater SFDs on 150 m to 1 km targets, representative of NEAs visited by space missions. Median dynamical lifetimes decrease with increasing a: sim1. 3 yr (G1), sim2. 1 yr (G2), and sim0. 9 yr (G3). NEACs in G2–G3 maintain nearly constant MB residence fractions, with short intervals of full containment, while G1 exhibits stronger 0–0. 8 oscillations (median sim0. 55 for sim10⁶ yr). DART-analog impacts occur on sim10⁵ yr timescales for targets łesssim300 m (rising to sim10⁶ yr for larger bodies), whereas catastrophic collisions are negligible within NEAC lifetimes. Over a timescale of 1 Myr, collisional erosion reduces the metre-sized NEA population by only 0. 1–1. 4%, depending on QD^*. Comparisons with the observed crater SFDs on Bennu, Didymos, and Ryugu indicate target strengths of Y Pa for Bennu, young effective surface ages for Didymos, and short crater-retention times of the order of 10⁴--10⁵ yr for craters with diameters <100 m on Ryugu, consistent with rapid resurfacing. NEACs spend a substantial fraction of their lifetimes inside the MB and undergo frequent small-scale impacts; however, collisions weakly modify the global NEA SFD on Myr timescales. Our combined dynamical-collisional framework constrains NEAC lifetimes, orbital pathways, collisional timescales, and surface processing.
Zain et al. (Fri,) studied this question.