Population of the Oort cloud rocky meteoroids from the AMOS Meteor Network with implications for the Solar System cosmogony

Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia

^★ Corresponding author: vitalii.kuksenko@fmph.uniba.sk

Received: 3 April 2025
Accepted: 16 October 2025

Abstract

Context. Recent observations of small Solar System bodies (comets, meteors) showed unexpected evidence of the presence of refractory objects in the Oort cloud. Models of the origin of the Solar System produce different predictions for their population. Therefore, measurements of the rocky population of the Oort cloud can be used as an observational constraint for different cosmogonic models.

Aims. The aim of this work is to investigate how data obtained from meteor observations can be used as a tool for distinguishing among the existing cosmogonic models.

Methods. We analyzed two databases collected by cameras of the All-Sky Meteor Orbit System located on the Canary Islands and in Chile. We searched for unusually strong rocky meteoroids (P_E > −4.6) on cometary orbits (T_J < 2) with lower mass limits of 10 g and 1 g originating in the Oort cloud. We then calculated fluxes of meteors of different compositions. Asteroidal and cometary meteor fluxes were used to estimate the ratio of icy and rocky components of the Oort cloud, which we compared with predictions of different cosmogonic models.

Results. Our results, combined with the results of other authors, showed that ∼5% of the Oort cloud objects with masses larger than 10 g are rocky. Our estimate is closest to the theoretical prediction of the Grand Tack cosmogonic model. The population of rocky objects in the Oort cloud with masses larger than 1 g is ~11.7%.

Conclusions. The development of more precise orbital and material classifications and the improvement of observational techniques and numerical simulations are needed. The best approach is to combine data from different meteor networks and databases.