Pre-airburst Orbital Evolution of Earth's Impactor 2018 LA: An Update

TL;DR

This study updates the orbital analysis of asteroid 2018 LA, exploring its potential link to a larger asteroid and assessing its impact trajectory using orbit similarity metrics and simulations.

Contribution

It provides new orbit determination data and suggests a possible recent fragmentation origin from asteroid 2013 BO73.

Findings

Confirmed a dynamical grouping related to 2018 LA

Proposed a potential link to asteroid 2013 BO73

Suggested spectroscopic observations could confirm compositional similarities

Abstract

Apollo meteoroid 2018 LA has become only the third natural object ever to be discovered prior to causing a meteor airburst and just the second one to have its meteorites recovered (at Botswana's Central Kalahari Game Reserve). Here, we use the latest orbit determination of 2018 LA (solution date 18-July-2018) to search for minor bodies moving in paths comparable to that of 2018 LA using the D-criteria, which are metrics to study orbit similarity, and N-body simulations. Our results further confirm the existence of a dynamical grouping of asteroids that might be related to 2018 LA and show that the impactor could be a recent fragment spawned by a larger object, the 550-m wide, potentially hazardous asteroid (454100) 2013 BO73. Spectroscopic observations of 454100 during its next flyby with our planet (brightest at an apparent visual magnitude of 18.4 on 2018 mid-November) may confirm or deny a putative similar chemical composition to that of the recovered meteorites of 2018 LA.