Mystery of carbonaceous meteorites apparently solved

Fewer carbon-containing meteorites hit the earth than expected because a large proportion of the material is destroyed by the sun and the earth's atmosphere beforehand. This has been discovered by an international research team, which says it has solved a particularly old mystery in space research.

While asteroids usually also contain carbon, this applies to only a few percent of all fragments from space found on Earth. It is now clear that the sun and the earth's atmosphere act as filters that sort out most meteoroids before they can hit the earth.

Central to the origin of life

Carbon-rich C-type asteroids are among the oldest objects in the solar system and make up around three quarters of all asteroids. At the same time, the material of only about 5 percent of all meteorites matches these asteroids. This disparity has long been a great mystery, explains the research team led by co-author Hadrien Devillepoix from Curtin University. It had already been assumed that many would not survive the immense heat of the fall through the Earth's atmosphere, he adds. Now, however, it has been discovered that many do not even make it that far. During their repeated flybys of the sun, they are repeatedly heated until they finally break apart.

While there are comparatively few carbon-rich meteorites for this reason, they are of particular interest to researchers because they contain the basic building blocks for the development of life. The question of the reason for the large disparity was therefore of greater importance. For the analysis, the research team analyzed 8500 meteoroids – i.e., small objects orbiting the sun – and evaluated data from 19 observation networks for fireballs. It is the most comprehensive study of its kind. The results have now been published in the journal Nature Astronomy.

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(mho)