Abstract

Abstract. We analyze the dynamical evolution of asteroidal fragments released in the Flora region, near the inner edge of the main asteroid belt, and drifting into the ν6 secular resonance due to Yarkovsky non-gravitational effects. We find that fragments 5 to 20 m in size evolve under the “seasonal ” Yarkovsky effect which causes a secular semimajor axis decay; they reach ν6 after a time shorter than their collisional lifetime when they start within about 0.05 to 0.2 AU out of the resonance. Metalrich fragments drift slower but have have much longer lifetimes than stony ones, so they drift farther from their formation site and sample a wider portion of the inner belt. Fragments around 100 m in size are mainly influenced by the “diurnal ” Yarkovsky effect if their surface is covered by a (thin) regolith layer; this causes a random walk in semimajor axis controlled by impacts which reorient the spin axis. Within their lifetime of ≈ 100 Myr