The National Museum of Nature and Science, the National Institute of Polar Research, and Kyushu University analyzed meteorites that fell in Komaki City, Aichi Prefecture last year, and confirmed the classification as "L6 ordinary chondrite."It was registered as "Komaki" by the Meteoritical Society of Japan.

 A meteorite fell on a private house in Komaki City, Aichi Prefecture, around 2018:9 on September 26, 22 (Wednesday).As a result of gamma-ray measurement of black debris scattered in the garden by the National Museum of Nature and Science, the radionuclides aluminum-30, sodium-26, manganese-22, etc. generated by cosmic rays were detected.I confirmed that it was a meteorite that had recently fallen.

 At the National Institute of Polar Research, take about 550 g of a sample for preservation and analysis from the main material (weight 20 g), make a polished flakes from about 1 g of the sample, observe the structure with an optical microscope, and minerals with an electron probe microanalyzer. The composition was analyzed.As a result, meteorites are usually classified as chondrites (spherical meteorites), and the chemical group is found to be L from the mineral composition.In addition, relatively coarse-grained (50 μm or more) plagioclase was observed, and the petrological type was 6.This combination is called "L6 chondrite" and is called the largest chondrite group.

 Noble gas is analyzed from a small amount (0.05g) of sample at Kyushu University.Analysis of argon reveals that it was formed shortly after the solar system was born about 46 billion years ago.Also, from the analysis of neon, the cosmic ray irradiation age (the period when the meteorite separated from the original celestial body and became a small fragment) is about 2510 million years, which is about 2000 to 3000 million years, which is the same as many L chondrites. was.It is believed that the original celestial body of the L chondrite was destroyed by a collision during this period, and many small fragments were formed.

 With the analysis results, we applied for registration with the Meteoritical Society of Japan as "Komaki", which is named after the city of Komaki where the meteorite fell.It was reviewed and voted on by the naming committee of the Society and approved and registered on February 2.

reference:[Kyushu University] The classification of meteorites that fell in Komaki City, Aichi Prefecture was confirmed and registered with the Meteoritical Society of Japan as "Komaki Meteorite" (PDF).

University Journal Online Editorial Department

This is the online editorial department of the university journal.
Articles are written by editorial staff who have a high level of knowledge and interest in universities and education.