Baked before breaking into bits: evidence for Atira-type asteroid splits

Abstract

Current near-Earth asteroid orbital models cannot reproduce the observed populations close to the Sun. Supercatastrophic and tidal disruptions may explain the differences between theoretical models and observational data. Here, we explore the distributions of mutual nodal distances and the angular separation of perihelia of the known Atiras looking for evidence of past splittings. We find a number of pairs, trios, and one quartet of Atiras with mutual nodal distances as short as 0.001 au at the orbits of Mercury and Venus. The smallest of these highly correlated objects is 2023 WK3. Fragmentation or binary disruption may have triggered the recent formation of the unusual pair made of 594913 'Ayló'chaxnim (2020 AV2) and 2012 VE46 with both mutual nodal distance and angular separation of perihelia in the first percentile of the distribution, making 2012 VE46 a robust candidate to being a former moon or piece of 'Ayló'chaxnim.