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1999 Leonid MAC Campaign, Some Scientific Results

Jane Houston Jones


In late April, the International Leonid Multi Instrument Aircraft Campaign (Leonid-MAC) Workshop was held in Tel Aviv, Israel. NASA, the U.S. Air Force, and the Israel Space Agency sponsored the event. Most of the researchers who conducted airborne experiments on the Leonid Multi-instrument Aircraft Campaign last November attended the workshop. Many other researchers with projects conducted during land based campaigns also presented their results.

The Leonid meteor shower offered unprecedented opportunities to address outstanding issues in the areas of Planetary Astronomy, Suborbital Magnetospheric, Ionospheric, Thermospheric, and Mesospheric (MITM), and Astrobiology. The Leonid meteor shower also presented opportunities to study the dynamics of the upper atmosphere, and issues that relate to the satellite impact hazard of meteor storms.

Some highlights from the Leonid MAC Workshop:

Astrobiology:

Leonid storm lightcurves different from 1998 return (I. Murray et al., Regina University)

CN is absent in near-UV (R. Rairden et al., Lockheed Martin)

Unusual meteor shapes at high 135-200 km altitude (P. Spurny et al., Ondrejov Observatory)

New meteor models from rarefied flow around a meteoroid. Direct Simulation Monte Carlo techniques explain meteor temperatures (I. Boyd et. al., Michigan University)

First measurement of temperature decay in air plasma of bright bolide (J. Borovicka et al., Ondrjov Observatory)

Unusual beading in meteor train emission (M. Taylor et al. Utah State Univ.)

First mid-IR spectra of persistent trains show warm air emissions (R. Russell, G. Rosano et al., The Aerospace Corp.)

Shower affects airglow chemistry (J. Kristl et al., AFRL)

Impact hazard:

Acute impact probability about 2.5 percent during 1999 Leonid storm (H. Yano, ISAS)

Near-real time reporting a success (M. Treu, USAF/XOR)

Storm profile Lorentz curve: offers possibility for empirical measurements of trailet cross section perpendicular to Earth's orbit and dust density fall off away from comet position (P. Jenniskens, SETI Inst.)

Good prospects for further meteor storms in 2001 and 2002 (D. Asher, Armaugh Observatory)

Environment:

First elves observed over Europe are also first confirmation of EMP pulse theory (M. Taylor, L. Gardner, et al., Utah State University)

Numerous unusual short duration VLF emissions in 1-20 kHz range consistent with meteoric origin (C. Price, Tel Aviv University)

Brief flashes against lunar disk consistent with impacts on the Moon (L. Bellott et al., Univ. of Tenerife)

Techniques:

Airborne observations up to 7 times more effective in counting meteors than ground-based efforts from Calar Alto (D. Koschny, ESTEC)

NASA is presently in a phase of information gathering to gear up for the next (and final) generation missions in the Leonid MAC effort for the years 2000-2002.

The planned one-plane and low-cost 2000 Leonid MAC mission is a technology testbed for new astrobiology experiments for the final two missions in 2001 and 2002 when a storm is expected. Unaffected by scattered Moonlight, this mission will collect fundamental data on dust distribution perpendicular to Earth's orbit and along the dust trail away from the comet. The mission banks on the fact that both the 1866 and 1932 trailets are best observed from the eastern USA in consecutive nights.

More detail, in the form of extracts of each workshop speaker's topic can be read on the Leonid MAC Workshop 2000 website. http://leonid.arc.nasa.gov/workshops/


Mail to: Jane Houston Jones
Copyright © 2000 San Jose Astronomical Association
Last updated: July 19, 2007

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