Two Robust Interstellar Meteor Candidates in the Post-2018 CNEOS Fireball Database

TL;DR

This paper identifies two potential interstellar meteors in the CNEOS fireball database, using a calibrated uncertainty model and Monte Carlo simulations to confirm their hyperbolic trajectories and interstellar origins.

Contribution

The study introduces a new method applying an empirically calibrated uncertainty model and extensive simulations to identify interstellar meteors in existing fireball data.

Findings

Two candidate interstellar meteors with speeds exceeding escape velocity.

Both candidates have negligible probability of being gravitationally bound.

Uncertainties are unlikely to be underestimated enough to change their interstellar classification.

Abstract

We report the identification of two previously unrecognized interstellar meteor candidates in the NASA CNEOS fireball database. Using the empirically calibrated low-discrepancy uncertainty model of Pe\~na-Asensio et al.\ (2025) for post-2018 CNEOS velocity accuracy (1$\sigma$: speed 0.55~km~s$^{-1}$, right ascension 1.35$^\circ$, declination 0.84$^\circ$), we transform CNEOS velocity vectors to heliocentric orbits and assess interstellar candidacy via $10^{6}$-draw Monte Carlo simulations. Two post-2018 events have heliocentric speeds robustly exceeding the Solar System escape speed. CNEOS-22 (2022-07-28; 6.0$^\circ$S, 86.9$^\circ$W; eastern tropical Pacific) has $v_{\rm hel}=46.98$~km~s$^{-1}$, exceeding escape by $\Delta = 5.18 \pm 0.60$~km~s$^{-1}$ ($z_{\Delta}=8.7\sigma$), with interstellar speed $v_{\infty,\odot}=21.5$~km~s$^{-1}$. CNEOS-25 (2025-02-12; 73.4$^\circ$N, 49.3$^\circ$E; Barents Sea) has $v_{\rm hel}=45.63$~km~s$^{-1}$, exceeding escape by $\Delta = 3.22 \pm 0.58$~km~s$^{-1}$ ($z_{\Delta}=5.5\sigma$), with $v_{\infty,\odot}=16.9$~km~s$^{-1}$. For both events, none of $10^{6}$ realizations yield a gravitationally bound orbit ($p_{\rm bound} < 3\times 10^{-6}$). The adopted error model would need to underestimate the true uncertainties by factors of 5--9 for either candidate to be marginally bound.