Météore interstellaire polaire : un nouvel invité venu des profondeurs de la Galaxie ✛ ✦

Résumé original

tel que rédigé par les auteurs, en anglais arXiv:2606.04379v1

We report a newly identified polar interstellar meteor candidate, labeled polarIM, detected on 2026-04-01 02:13:14 UTC at latitude $$-41.9^\circ$$, longitude $$-54.7^\circ$$, and altitude 90.5 km over the South Atlantic Ocean, east of Argentina. We transform the reported Earth-fixed velocity vector $$(+3.6,\,-34.6,\,+59.8)~\mathrm{km\,s^{-1}}$$ to an inertial geocentric state, remove Earth's gravitational acceleration with a two-body hyperbolic model, add the JPL Horizons heliocentric velocity of Earth, and test the resulting heliocentric orbit against solar escape speed. The final velocity component in the polar ($$z$$) direction of $$+47.09~\mathrm{km\,s^{-1}}$$ exceeds by itself the local solar escape speed $$v_{\rm esc,\odot}=42.14~\mathrm{km\,s^{-1}}$$. The full heliocentric speed is $$v_{\rm hel}=51.73~\mathrm{km\,s^{-1}}$$, corresponding to positive heliocentric specific energy $$\varepsilon_\odot=+450.1~\mathrm{km^2\,s^{-2}}$$, heliocentric excess speed $$v_{\infty,\odot}=30.00~\mathrm{km\,s^{-1}}$$, and a two-body inclination $$i=89.4^\circ$$. We propagate measurement uncertainty through 1,000,000 Monte Carlo realizations using the empirical post-2018 low-discrepancy CNEOS error model of Pena-Asensio et al. (2025), with $$\sigma_v=0.55~\mathrm{km\,s^{-1}}$$, $$\sigma_{\rm RA}=1.35^\circ$$, and $$\sigma_{\rm Dec}=0.84^\circ$$. No realization yields a bound heliocentric orbit, giving a statistical confidence on the interstellar fraction of $$>99.9997\%$$. The Monte Carlo margin above escape is $$\langle\Delta\rangle=9.60\pm0.75~\mathrm{km\,s^{-1}}$$, corresponding to a $$12.82\sigma$$ margin-to-scatter ratio under the adopted perturbation model. The result identifies polarIM as the highest-margin post-2018 candidate in the CNEOS catalog.