Figure: Collecting meteoroid dust particles from snow layers in Antarctica.
COLLECTING METEORIC DEBRIS FROM SNOW COVER
In 1997, Jean Duprat and Michel Maurette of the University of Paris at
Orsay (CSNSM) and coworkers
in Denmark and England launched a long-term program to collect micrometeorites from historical
Leonid showers in both Greenland and the Antarctic ice cap. The snow is
melted layer by layer, thus collecting meteoric debris from specific years.
In this way, Maurette et al. hope to find an increase of
extraterrestrial dust in 1966 and from recent Leonid storms.
Until now, 2 expeditions were executed in central Antarctica,
at the station CONCORDIA-DOME C located at S75ÿý, E123ÿý.
The experimental device is a stainless steel double-tank snow smelter (using a propane gas
heater). The water is then filtered through 25 and/or 30 micron filters. The filters are then
examined in the field in clean conditions with a binocular microscope.
In January 2000 and January 2002 we collected samples from snow layers including the
1966 level to search for possible variations in intensity and/or composition of the
micrometeorites flux. The analysis of the particles of extraterrestrial origin is in progress.
The picture above was taken during the first expedition at CONCORDIA-DOME C in january 2000
and shows the trench from which the snow was recovered.
The picture to the left shows one of the micrometeorites collected from the antarctic snow.
So far, no particles can be linked to the Leonid shower.
With the help of Prof. Claus Hammer (NBI Copenhagen-DK), and the financial support of the Danish Research Council Dupras et al. are currently organising a new collect
in central Greenland in june 2003.
The main objective will be, if the 2002 storm is intense enough, to try to collect it in
surface snow layers using the same technique we developed for Antarctic collects.
Read more here.