Typical Leonids puzzles
Disturbances in the electric field
This is a very new field of study concerning the Leonids. In 2001, in Australia, scientists tried to measure for the first time the fluctuations in the terrestrial electric field caused by the meteors when they enter the atmosphere. Scientists are not sure why this happens. It is a very complex measurement, because you have to be far from any other electrical source (such as electrical power lines and other electrical equipments) to avoid interference. In 2001 they took measurements only during one of the two peaks of the storm, and did not have enough data to exclude all external sources of disturbances, such as thunderstorms. This year they plan to do a continuous measurement over several days.
Homogeneity of the comet's surface
By examining the brightness of the meteors by means of their observed light curves when they disintegrate in the atmosphere, scientists can infer some of the physical characteristics of meteors. If the luminosity rises steadily and then all of a sudden stops, it was probably a stronger and bigger isolated piece of meteor. On the other hand, if the luminosity has an initial burst and then slowly disappears in a trail, the particle consists of fragile material or just belongs to a dust cloud. Scientists suspect that the parent comet does not have a homogenous surface, but consists of different parts, some harder (like a rock), others weaker (like a snowflake).
Chemical composition
With the help of an objective grating, an instrument very similar to a prism, used to decompose the light into all its coloured components, scientists can obtain information on the chemical composition of the flecks constituting the meteor storms. The elements they observe when they look at the meteors are: oxygen (which belongs to the atmosphere breaking the impact), iron and manganese, which are elements belonging to the meteors and thus to the comet. The atmospheric light emission is the one contributing the most to the light curve of a meteor. The scientific question scientists want to address this year is: do particles belonging to the two different trails have the same chemical composition?
Combining views
Beside these main topics, in 2002 scientists are hoping to be lucky: they are prepared to exploit other observatories to gain some extra information. They are ready to use the Pico Veleta 30-metre radio telescope: if a meteor leaves a long-lasting trail, they will try to determine which molecules it contains. They are ready to activate the Proba spacecraft in the hope to demonstrate that meteors can be observed also from space. By means of the ESA 1.2-metre telescope in Tenerife they will try to measure precisely from which area of the sky the meteors come from.