Metallic abundances of the 2002 Leonid meteor deduced from high-definition TV spectra

Abstract

High-definition TV spectra in the ultraviolet-visible region were obtained during the 2002 Leonid aircraft campaign. We analyze the spectra of the brightest fireball that appeared at 03 h 47 m 54 s UT on Nov. 19, 2002 and identify the neutral atoms, mainly MgI, FeI, CaI, and NaI in the observed wavelengths between 300-650 nm. The singly ionized atomic emissions, CaII and MgII lines, also appeared in the spectrum in several epochs during the series of video frames. From analysis of the spectra, time variation in the abundances of metallic atoms, along with their electronic excitation and blackbody temperatures, were obtained assuming the Local Thermal Equilibrium (LTE) condition. Both Fe and Ca abundances relative to Mg are lower than the solar abundance, while Na is slightly higher. We found correlation between the excitation temperature and the abundance of Ca, which suggests incomplete evaporation of the Ca due to intrinsic refractoriness. A search for bands of CHON-related molecules, such as OH and CN, is not successful in the brightest fireball in this study.