ASTÉROÏDES, COMÈTES, MÉTÉORES et ÉPHÉMÉRIDES (ACME)

Institut de mécanique céleste et de calcul des éphémérides,
Observatoire de Paris, UMR 8028 du CNRS
77 avenue Denfert-Rochereau, 75014 Paris, France
Contact : acme.imcce@obspm.fr

 
Présentation Membres Publications
Astéroïdes Comètes Météores Ephémérides
 
Equipe ACME

puce Meteors are streaks of light caused by the fast entry of meteoroids (=small rocks in the solar system) in a planetary atmosphere. They are also known as 'shooting stars'.

puce A Meteoroid is a small body of the solar system (basically a rock), considerably smaller than an asteroid, and considerably bigger than a molecule or an atom (typically from a few microns to a few meters in size). When a meteoroid enters the atmosphere of the Earth, it collides with the molecules of the air at an altitude of roughly 100 km from the ground. Meteoroid are reaching the atmosphere at a fantastic velocity: 11 to 71 km/s, that is 2 to 10 times as fast as the shuttle at its reentry (or 40 to 240 times as fast as a bullet). Because of that, each collision is energetic enough to remove a piece of the meteoroid, which disintegrates this way. A plasma (electrons and ions) is created, and a fraction of the energy is converted into light. This is how "shooting stars" (meteors) are created. Most of the time, the meteoroid disintegrates completely before it reaches 50km of altitude.

puce A Meteorite is a meteoroid big and/or slow enough to survive the entry in the atmosphere. It falls on the ground and can be found by anybody. If the meteorite is large and fast enough at the time it reaches the ground, it creates a crater.

puce Research on meteors at IMCCE focuses first on the dynamical aspects of meteoroids streams, that is how they are ejected from comets into our solar system, and what subsequently happens to them, as they revolve around the Sun. Planetary gravitational perturbations as well as radiative forces can make their behaviour quite complicated, that only heavy numerical simulations (performed at CINES) can address. The goal is not only to understand but also to forecast the meteor showers, in order to validate our understanding.

The second aspect of the research performed at IMCCE is an effort to observe the meteors but better understand their origin (and hence their parent body and age) and composition. Several observation projects as well as observation campaigns are going on at IMCCE.

Caution : This Website was created with the Ministère de l'Education Nationale, the CNRS and the CNES support. Any use of the data published on this website requires the IMCCE agreement..