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LEONID DAILY NEWS: October 21, 2002

Dr. John Plane

Dr. John Plane at COSPAR/World Space Congress special session on Leonid storms.


A special session on "Meteor Induced Chemistry, Ablation Products, and Dust in the Middle and Upper Atmosphere" was organized by Peter Jenniskens as a joint COSPAR/IAC event at the World Space Congress in Houston, TX, on October 16.

Hajime Yano of ISAS, Japan, summarized results from the Leonid MAC Workshop and discussed the satellite impact hazard issue. Co-chair John Plane, who studies the chemical reactions of iron atoms in the upper atmosphere in laboratory conditions at the University of East Anglia, discussed the role of meteoric smoke in providing condensation nuclei for noctilucent clouds in the upper mesosphere, forming sulphuric acid particles in the stratospheric layer, and in fertilizing the Fe-deficient Southern Ocean. Frans Rietmeijer of the University of New Mexico calculated that the expected middle-atmospheric carbon abundance is a high C/Fe (at.) = 0.3 and C/Mg (at.) = 0.25.

John Zinn of Los Alamos National Laboratory presented a model of meteor (train) emission, predicting strong 760 nm emission of molecular oxygen, which may provide insight into the recent detection of such emission in meteor afterglow. Leonid MAC Instrument PI Mike Taylor of Utah State University presented results on the ejection of small meteoroid fragments from rapidly rotating meteoroids. Peter Jenniskens discussed quantative data on meteor plasma temperatures and abundances from 2001 Leonid MAC data and the latest results by Hans Stenbeak-Nielsen on the peculiar shock wave in high frame-rate images.

S.P. Gupta of the Physical Research Laboratory at Ahmedabad in India reported results from the first (and only) rocket experiment during the Leonid storm of 1999. A possible detection of plasma wave occilations in the frequency range of 2 kHz near 105 km altitude was made at the peak of the 1999 Leonid storm on Nov 18 and (less strong) during a second flight on Nov. 20.

Finally, J.F. Carbary and coworkers of John Hopkins University/APL presented further ultraviolet spectroscopic data from a second Leonid spectrum observed by the MSX satellite (see earlier result). The spectrum of a bright fireball detected in 1999 shows emissions of oxygen, nitrogen and hydrogen at short wavelengths between 110 and 130 nm and strong Mg+ emission at 280 nm, but only a weak Mg emission at 285 nm.

Previous news items:
Oct 21 - Highlights COSPAR/World Space Congress
Aug 31 - First UV spectrum: Leonid from space
Dec 11 - Shocking Leonid
Dec 01 - Moon impacts
Nov 26 - Near-IR persistent train emission
Nov 24 - Results of near-real time flux measurements
Nov 22 - Wowh! Optical meteor spectra
Dec. 25 - Ursid shower circular IMO
Dec. 24 - Ursid shows early release of sodium
Dec. 23 - Ursid outburst confirmed
Dec. 18 - Dec 22 Ursid outburst
Nov. 20 - A bacterial fingerprint?
Nov. 15 - HCN disappears mysteriously
Nov. 14 - Meteor shower from space
Nov. 13 - Organic fingerprint
Nov. 12 - Train airglow chemistry
Nov. 11 - Hard bits and persisting glows
Nov. 10 - Meteoroid debris detected
Nov. 09 - New meteor picture
Nov. 08 - Spin city
Nov. 07 - Meteors affect atmospheric chemistry
Nov. 06 - Listen to this!
Nov. 04 - Fear of heights?
Nov. 03 - The pale (infra-red) dot
Nov. 02 - Twin showers
Nov. 01 - Leonids approaching Earth
Oct. 31 - Prospects for Moon Impact Studies
Oct. 30 - Comet dust crumbled less fine
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Results of this research were published in a special issue of Advances in Space Research.

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