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Aubrite meteorite from asteroid 2024 BX1, photographed at the Museum für Naturkunde Berlin by Laura Kranich, a master’s student at the Freie Universität and member of the Arbeitskreis Meteore, who participated in the search and found this meteorite near the town of Ribbeck, Germany. Credit: Museum für Naturkunde Berlin by Laura Kranic
Jenniskens’ collaborators at the Museum für Naturkunde officially announced that the first examinations of one of these pieces with an electron beam microprobe demonstrate the typical mineralogy and chemical composition of an aubrite-type achondrite.
The official classification now lines up with what many suspected just by looking at images of the strange meteorites that fell near Berlin on January 21, 2024. They belong to a rare group called “aubrites.”
“They were devilishly difficult to find because, from a distance, they look like other rocks on Earth,” said Dr. Peter Jenniskens, a meteorite astronomer at the SETI Institute. “Close up, not so much.”
Jenniskens traveled from San Francisco to Berlin to search the fields just south of the village of Ribbeck with Museum für Naturkunde (MfN) researcher Dr. Lutz Hecht, guiding a team of students and staff from MfN, the Freie Universität Berlin , the Deutches Zentrum. für Luft und Raumfahrt and the Technische Universität Berlin in the days after autumn.
The detection challenge
“Even with the magnificent indications of meteorite astronomers, Drs. Pavel Spurný, Jiří Borovička and Lukáyes Shrbený of the Astronomical Institute of the Czech Academy of Sciences, who calculated how strong winds carried the meteorites and predicted that they could be rare enstatite-rich meteorites based on the light emitted by the fireball, our search team initially could not easily detect them on the ground,” Jenniskens said.
Unlike other meteorites that have a thin black glass crust due to atmospheric heat, these meteorites have a mostly translucent glass crust.
“We only discovered the meteorites after a Polish team of meteorite hunters identified the first find and were able to show us what to look for,” Jenniskens said. “After that, our first findings were quickly made by Freie Universität students Dominik Dieter and Cara Weihe.”
Importance of meteorite collections
The meteorites are fragments of the small asteroid 2024 BX1, first detected with a telescope at the Konkoly Observatory in Hungary by astronomer Dr. Krisztián Sárneczky, tracked and then predicted to impact the Earth’s atmosphere by POTESA’s Scout and Meerkat Asteroid Guard impact risk assessment systems, with Davide Farnocchia from JPL/Caltech provided frequent trajectory updates and eventually sparked a bright fireball that was seen and filmed. This was Jenniskens’ fourth guided recovery from such a small asteroid impact, following a 2008 impact in Sudan, a 2018 impact in Botswana, and a 2023 impact in France.
Jenniskens’ collaborators at the Museum für Naturkunde officially announced today that the first examinations of one of these pieces with an electron beam microprobe demonstrate the typical mineralogy and chemical composition of an aubrite-type achondrite. This result was presented to the International Nomenclature Commission of the Meteoritic Society on February 2, 2024 for examination and confirmation.
The meteorite’s name comes from the town of Aubrés in France, where a similar meteorite fell on September 14, 1836. The museum has a fragment of it in the collection.
“Based on this evidence, we were able to make a rough classification relatively quickly,” said Dr. Ansgar Greshake, chief scientist of the museum’s meteorite collection. “This underlines the immense importance of collections for research. “So far there is only material from eleven other falls of this type observed in meteorite collections around the world.”
“Aubrites don’t look like what people usually imagine meteorites to be like. Aubrites look more like a gray granite and are mainly composed of magnesium silicates, enstatite and forsterite,” explained Christopher Hamann of the Museum of Nature, who was involved in the initial classification and participated in the search. “It hardly contains any iron and the glassy crust, which is usually a good way to recognize meteorites, looks completely different from most other meteorites. Therefore, aubrites are difficult to detect in the field.”