Recent arrivals to the main asteroid belt

AbstractThe region where the main asteroid belt is now located may have started empty, to become populated early in the history of the Solar system with material scattered outward by the terrestrial planets and inward by the giant planets. These dynamical pathways toward the main belt may still be active today. Here, we present results from a data mining experiment aimed at singling out present-day members of the main asteroid belt that may have reached the belt during the last few hundred years. Probable newcomers include 2003 $$\hbox {BM}_{1}$$ BM 1 , 2007 $$\hbox {RS}_{62}$$ RS 62 , 457175 (2008 $$\hbox {GO}_{98}$$ GO 98 ), 2010 $$\hbox {BG}_{18}$$ BG 18 , 2010 $$\hbox {JC}_{58}$$ JC 58 , 2010 $$\hbox {JV}_{52}$$ JV 52 , 2010 $$\hbox {KS}_{6}$$ KS 6 , 2010 $$\hbox {LD}_{74}$$ LD 74 , 2010 $$\hbox {OX}_{38}$$ OX 38 , 2011 $$\hbox {QQ}_{99}$$ QQ 99 , 2013 $$\hbox {HT}_{149}$$ HT 149 , 2015 $$\hbox {BH}_{103}$$ BH 103 , 2015 $$\hbox {BU}_{525}$$ BU 525 , 2015 $$\hbox {RO}_{127}$$ RO 127 , 2015 $$\hbox {RS}_{139}$$ RS 139 , 2016 $$\hbox {PC}_{41}$$ PC 41 , 2016 $$\hbox {UU}_{231}$$ UU 231 , 2020 $$\hbox {SA}_{75}$$ SA 75 , 2020 $$\hbox {UO}_{43}$$ UO 43 , and 2021 $$\hbox {UJ}_{5}$$ UJ 5 , all of them in the outer belt. Some of these candidates may have been inserted in their current orbits after experiencing relatively recent close encounters with Jupiter. We also investigated the likely source regions of such new arrivals. Asteroid 2020 $$\hbox {UO}_{43}$$ UO 43 , if real, has a non-negligible probability of having an origin in the Oort cloud or even interstellar space. Asteroid 2003 $$\hbox {BM}_{1}$$ BM 1 may have come from the neighborhood of Uranus. However, most newcomers—including 457175, 2011 $$\hbox {QQ}_{99}$$ QQ 99 , and 2021 $$\hbox {UJ}_{5}$$ UJ 5 —might have had an origin in Centaur orbital space. The reliability of these findings is assessed within the context of the uncertainties of the available orbit determinations.