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Leonids 2001 Observing Campaigns

Australia campaign

Copyright: 2001 Shigemi Numazawa, Japan Planetarium Laboratory; courtesy Sky & Telescope

The Leonid meteors are coming - again! And this time, ESA scientists will be avidly awaiting their arrival from the other side of the world, in the Australian outback.

In addition to their studies of the meteor shower, the team intends to test a new prototype of an instrument that is being developed for future planetary missions to Mars, Mercury and the Moon.

Over the next few weeks, their adventures and discoveries will be posted on the ESA science web site, so watch this space!

In the meantime, read about why they are going to Australia and what they intend to do there.

Why go to Australia?

Studies of the Leonids, the famous annual meteor shower coming from Comet Tempel-Tuttle, suggest that the number of visible meteors will reach a peak of perhaps 15000 per hour on the night of 18-19 November. Unfortunately, the Leonids will be below the horizon in Europe at that time. However, the Far East and Australia should be well placed to see the light show.

"Although Mongolia and China are slightly more attractive when it comes to the best observing conditions for the predicted Leonid peaks, we have decided to go to the Australian desert," said ESA scientist Detlef Koschny.

"We took into account the cloud-free atmospheric conditions, the ease of access and the familiar language," he explained. "But our decision was also driven by the fact that we can combine our meteor campaign with a test programme for a prototype of a new scientific instrument."

Lake Eda

ESA's team of Australian adventurers is made up of four scientists. Detlef Koschny, Joe Zender and André Knöfel will be looking for Leonids, while Roland Trautner will be carrying out trials with a prototype instrument, called the Mutual Impedance probe, and measuring changes in the electric field of the atmosphere. The fifth member of the group, Olivier Witasse, will be supporting their efforts from the European Space Research and Technology Centre (ESTEC).

The team's travels will begin with a flight from the Netherlands on 10 November. After their arrival in Perth, they will pay a short visit to the New Norcia ground station which is being built to support ESA's Rosetta mission to Comet Wirtanen.

On arrival in Broome, 1500 km to the north of Perth, the team will collect their four-wheel drive camper cars for the expedition into the outback to their final destination - Lake Eda.

Shooting the Leonids

The campaign to observe the Leonid shower will take place between 15 and 19 November. In order to obtain stereo images of the Leonids, the team will set up two observation sites separated by 50 km.

At each location, the team will continually monitor the incoming Leonids with two image-intensified video cameras. A fifth, wide angle, video camera will obtain an 80 degree 'fish eye' view of the night sky.

"The primary objective of our campaign is to count the meteor trails and measure their brightness," said Koschny. "With the 'normal' cameras, we can record many more meteors than are visible to the naked eye."

"This will eventually enable us to calculate the changing numbers of meteors over the five-day observing period," he said. "We can then use this information to improve existing computer models of the many dust streams that are associated with Comet Tempel-Tuttle."

"We will also learn a lot about the size and type of material that is being incinerated by studying its speed and light curve - how each meteor trail brightens and dims as it burns up in the atmosphere," he said.

"The second video camera at each site will enable us to find out what the particles are made of," he added. "These cameras contain a grating that splits the light from the meteor trails into different colours. By analysing these colours, we can discover their chemical composition."

Electrifying Leonids

While his colleagues concentrate on visual observations of the Leonids, Roland Trautner will be attempting to record tiny changes in the electric field caused by the glowing meteor trails.

"We have a prototype of a sensitive electric field sensor that is very difficult to test in laboratory conditions," explained Trautner. "It is even difficult to use outdoors in the Netherlands because of background electrical 'noise'."

"So we decided to take it Australia, where we can test it without interference from other electrical sources and we can also take the opportunity to try an exciting experiment," he said.

"We hope to confirm or rule out the influence of meteor impacts on the electric field in our atmosphere," he explained. "We expect the brighter fireballs to ionise the atoms in the upper atmosphere. This should cause tiny fluctuations in the electric field. However, it is a very difficult measurement to make. If we succeed, it will be the first time this has ever been done."

Roland Trautner will be equally busy testing another instrument, the Mutual Impedance probe. Like the SESAME instrument on the Rosetta lander, the MI probe is designed to measure how easily electrical current flows through the ground. This is a particularly useful technique for detecting subsurface water or ice, and so has potential for future applications on the Moon, Mars or Mercury.

"During the daytime, I will be trying out a new instrument design and testing the capability of the probe to identify water in the subsoil," he said.

"It must be tested under conditions similar to those which can be found on many planetary bodies, so this region is a suitable place for these tests," said Trautner. "I am not sure when I will sleep!" he added.


Last Update: 28 September 2005

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