Scientists have summarized the results of all studies of the Flensburg meteorite. It turned out to contain the oldest carbonates in the entire solar system. The article was published in the journal Geochimica et Cosmochimica Acta.
In September 2019, a fireball flew over the North Sea coast. A day later, a resident of the German city of Flensburg found on his site a strange stone covered with a black crust. Friends advised him to report the find to the International Meteor Organization. So the scientists got a splinter of a car. The fact that the stone is a meteorite was indicated by cosmic radionuclides in its composition. It was divided into several parts, each of which was studied by different methods in laboratories around the world.
Until recently, the results of these studies were not generalized. But scientists have already reported on some properties of the meteorite. For example, it turned out that it belongs to carbonaceous chondrites. This type of chondrite formed the farthest from the Sun. They contain water or minerals, from which it can be concluded that there was water in the past. Such chondrites fall to Earth extremely rarely (they make up about five percent of all chondrites).
Scientists from Germany, USA, France, Switzerland and other countries have jointly published an article detailing the characteristics of the meteorite. The publication includes the results of all studies, its mineralogical, chemical and isotopic composition.
The authors estimated the age of carbonates in the rock. This required a complex isotopic analysis: the carbonate grains are extremely small, so the measurements were carried out in the range of several micrometers. The 53Mn isotope was used for the analysis. It accumulates in space objects and decays to 53Cr. By the ratio of the number of mother and daughter nuclei, it is possible to determine the age of an object if we are talking about billions of years. In the case of the Flensburg meteorite, this is about four and a half billion. Its parent asteroid and carbonates have been found to have formed between 2.6 and 3.4 million years after the formation of calcium and aluminum-rich inclusions (CAIs), which are considered to be among the first solids to form in the solar system.
These carbonates are a million years older than those found in other types of carbonaceous chondrites. Based on the isotopic composition, they emerged from the hot liquid shortly after the parent asteroid formed. This makes the Flensburg meteorite evidence of the existence of small water-rich objects in the early solar system. Perhaps it was these meteorites that brought water to Earth.