The dynamical evolution of a tubular Leonid persistent train

Citation
P. Jenniskens et al., The dynamical evolution of a tubular Leonid persistent train, EARTH MOON, 82-3, 2000, pp. 471-488
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
EARTH MOON AND PLANETS
ISSN journal
0167-9295 → ACNP
Volume
82-3
Year of publication
2000
Pages
471 - 488
Database
ISI
SICI code
0167-9295(2000)82-3:<471:TDEOAT>2.0.ZU;2-S
Abstract
The dynamical evolution of the persistent train of a bright Leonid meteor w as examined for evidence of the source of the luminosity and the physical c onditions in the meteor path. The train consisted of two parallel somewhat diffuse luminous tracks, interpreted as the walls of a tube. A general lack of wind shear along the trail allowed these structures to remain intact fo r nearly 200 s, from which it was possible to determine that the tubular st ructure expanded at a near constant 10.5 ms(-)1, independent of altitude be tween 86 and 97 km. An initial fast decrease of train intensity below 90 km was followed by an increase in intensity and then a gradual decrease at lo nger times, whereas at high altitudes the integrated intensity was nearly c onstant with time. These results are compared to a model that describes the dynamical evolution of the train by diffusion, following an initial rapid expansion of the hot gaseous trail behind the meteoroid. The train luminosi ty is produced by O (S-1) emission at 557 nm, driven by elevated atomic O l evels produced by the meteor impact, as well as chemiluminescent reactions of the ablated metals Na and Fe with O-3. Ozone is rapidly removed within t he train, both by thermal decomposition and catalytic destruction by the me tallic species. Hence, the brightest emission occurs at the edge of the tra in between outwardly diffusing metallic species and inwardly diffusing O-3. Although the model is able to account plausibly for a number of characteri stic features of the train evolution, significant discrepancies remain that cannot casily be resolved.