Statistical significance of meteorite-asteroid pairs using geocentric parameters

TL;DR

This study tests the statistical connection between meteorite falls and NEAs using geocentric parameters, finding no significant evidence of clustering or streams, suggesting meteorites mostly arrive independently.

Contribution

It introduces a method to assess the statistical significance of meteorite-asteroid associations using geocentric similarity functions and large datasets, with no detected clustering.

Findings

No significant clustering between meteorites and NEAs.

Streams, if present, constitute less than 0.1% of meteorite falls.

Physical processes may explain meteorite features without forming streams.

Abstract

Aims. We will test the statistical significance of meteorite-dropping fireballs and NEA clustering using the DN similarity function based on four geocentric quantities (U, theta, phi, and lambda). Methods. We calculated the cumulative similarity found between 46 meteorite falls, 535 potential meteorite-dropping fireballs, 20,516 NEAs maintained by NEODyS-2, along with 34,836 NEAs maintained by NASA/JPL HORIZONS. Statistical significance was estimated by either: (1) Kernel Density Estimation-based method to estimate the sporadic background distribution to draw random samples, or (2) applying a uniform random solar longitude (lambda). Each comparison to the synthetic sporadic population is repeated to estimate the 3-sigma region for which the cumulative similarity distribution is consistent with random association levels. Results. The observed DN cumulative similarity distribution between 46 instrumentally observed meteorite falls, 535 potential meteorite-dropping fireballs, and over 30k NEAs radiants (estimated using 6 different radiant methods) reveals no statistically significant excess of similarity between the populations consistent with streams. Conclusions. Based on nearly 600 fireball observations, there is no statistically significant clustering between meteorite falls and NEAs using geocentric impact parameters. If some meteorites arrive in streams, they make up less than ~0.1% of all falls. Recent asteroid or meteoroid physical processes could still explain features found in meteorites, but this activity is not producing distinguishable orbital streams or pairs.