Color and spectral characteristics of long-lived meteor trail formed by the Tunka bolide

The paper addresses color characteristics and possible spectral composition of emission of a long-lived (~40 min) meteor trail of uncommon geometry, which was formed due to the bolide passage in the Tunka Valley on November 17, 2017. Analysis of dynamics of RGB channels of the meteor trail colored image shows that during the first ~8 minutes the meteor trail emission might have been contributed by the ionization trail. The ionization trail was formed by particles of the meteor matter neutral and ionized components that were heated to high temperatures on the surface of the main meteoroid and separated from it. We also examine the discussed mechanism of heterogeneous chemical reactions occurring on the surface of meteoric dust (FeS, FeO, etc.) with participation of atoms and molecules of atmospheric gases. The yellowish color of the Tunka bolide meteor trail was assumed to be determined, first of all, by the emission of molecular nitrogen N₂ band within the 570–750 nm spectral range (the first positive system) and/or enhancement of NO*₂ continuum in heterogeneous chemical reactions. The meteor trail emission spectrum should also include relatively bright atomic lines and molecular bands of the meteoric matter and atmospheric gases FeI, MgI, CaI, SiI, NaI, FeO and SO₂, OI, OH, etc.