Recent arrivals to the main asteroid belt

Abstract

The 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 BM 1, 2007 RS 62, 457175 (2008 GO 98), 2010 BG 18, 2010 JC 58, 2010 JV 52, 2010 KS 6, 2010 LD 74, 2010 OX 38, 2011 QQ 99, 2013 HT 149, 2015 BH 103, 2015 BU 525, 2015 RO 127, 2015 RS 139, 2016 PC 41, 2016 UU 231, 2020 SA 75, 2020 UO 43, and 2021 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 UO 43, if real, has a non-negligible probability of having an origin in the Oort cloud or even interstellar space. Asteroid 2003 BM 1 may have come from the neighborhood of Uranus. However, most newcomers—including 457175, 2011 QQ 99, and 2021 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.