Waiting to make an impact: a probable excess of near-Earth asteroids in 2018 LA-like orbits. (arXiv:1811.11845v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Marcos_C/0/1/0/all/0/1">C. de la Fuente Marcos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marcos_R/0/1/0/all/0/1">R. de la Fuente Marcos</a>
Context. The discovery and tracking of 2018 LA marks only the third instance
in history that the parent body of a fireball has been identified before its
eventual disintegration in our atmosphere. The subsequent recovery of
meteorites from 2018 LA was only the second time materials from outer space
that reached the ground could be linked with certitude to a particular minor
body. However, meteoroids like 2018 LA and its forerunners, 2008 TC3 and 2014
AA, are perhaps fragments of larger members of the near-Earth object (NEO)
population. As the processes leading to the production of such fragments are
unlikely to spawn just one meteoroid per event, it is important to identify
putative siblings and plausible candidates from which the observed meteoroids
might have originated.
Aims. Here, we study the pre-impact orbital evolution of 2018 LA to place
this meteoroid within the dynamical context of other NEOs that follow similar
trajectories.
Methods. Our statistical analyses are based on results of direct N-body
calculations that use the latest orbit determinations and include perturbations
by the eight major planets, the Moon, the barycentre of the Pluto-Charon
system, and the three largest asteroids. A state-of-the-art NEO orbit model is
used to interpret our findings and a randomization test is applied to estimate
their statistical significance.
Results. We find a statistically significant excess of NEOs in 2018 LA-like
orbits; among these objects we find one impactor, 2018 LA, and the fourth
closest known passer-by, 2018 UA. A possible connection with the Chi-Scorpiids
meteor shower is also discussed. The largest known NEO with an orbit similar to
that of 2018 LA is the potentially hazardous asteroid (454100) 2013 BO73 and we
speculate that they originate from a common precursor via a collisional
cascade.
Context. The discovery and tracking of 2018 LA marks only the third instance
in history that the parent body of a fireball has been identified before its
eventual disintegration in our atmosphere. The subsequent recovery of
meteorites from 2018 LA was only the second time materials from outer space
that reached the ground could be linked with certitude to a particular minor
body. However, meteoroids like 2018 LA and its forerunners, 2008 TC3 and 2014
AA, are perhaps fragments of larger members of the near-Earth object (NEO)
population. As the processes leading to the production of such fragments are
unlikely to spawn just one meteoroid per event, it is important to identify
putative siblings and plausible candidates from which the observed meteoroids
might have originated.
Aims. Here, we study the pre-impact orbital evolution of 2018 LA to place
this meteoroid within the dynamical context of other NEOs that follow similar
trajectories.
Methods. Our statistical analyses are based on results of direct N-body
calculations that use the latest orbit determinations and include perturbations
by the eight major planets, the Moon, the barycentre of the Pluto-Charon
system, and the three largest asteroids. A state-of-the-art NEO orbit model is
used to interpret our findings and a randomization test is applied to estimate
their statistical significance.
Results. We find a statistically significant excess of NEOs in 2018 LA-like
orbits; among these objects we find one impactor, 2018 LA, and the fourth
closest known passer-by, 2018 UA. A possible connection with the Chi-Scorpiids
meteor shower is also discussed. The largest known NEO with an orbit similar to
that of 2018 LA is the potentially hazardous asteroid (454100) 2013 BO73 and we
speculate that they originate from a common precursor via a collisional
cascade.
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