Spectrum of a Leonid meteor from 110 to 860 nm Original Research Article

During the Leonid meteor shower on 18 November 1999, the five spectrographic imagers onboard the Midcourse Space Experiment (MSX) satellite recorded the first complete meteor spectra from 110 to 860 nm. The observation occurred at 00:23:36.2 UT, at which time satellite was pointed at a tangent altitude of 100 km over 37.2°N and 78.2°E. The spectrograph slits were oriented approximately parallel to the horizon, and the meteor passed approximately perpendicular through the slits’ fields of view. All five spectrographic images serendipitously observed the passage of the object and each recorded 1–2 frames of data. Common meteor emissions from iron, sodium, and oxygen were observed in the visible, but the ultraviolet spectrum displayed a wealth of new features. The most intense features appeared in the middle ultraviolet (250–300 nm) from neutral and singly ionized iron and singly ionized magnesium. Far ultraviolet (110–130 nm) features included oxygen and nitrogen, a bright hydrogen Lyman α emission, and ionized iron and magnesium emissions. Also seen in the far ultraviolet were weak but recognizable emissions from neutral carbon. The ultraviolet emissions were much stronger than those in the visible and near-infrared. The meteor had a visual magnitude of −2.8 at 100 km, but the energy of emissions in the ultraviolet (110–337 nm) exceeded the energy of the visible (337–560 nm) by a factor of at least 5. The new Lyman α and carbon emissions in the far UV as well as the overall intensity of the ultraviolet spectrum suggest important applications for ultraviolet observations of meteors.