Russian scientists examined a rare meteorite of the pallasite class


Another well-known pallasite is the Fukan meteorite. A
team of scientists from the Neutron Physics Laboratory of the Joint Institute for Nuclear Research (JINR) conducted a study of a fragment of a rare meteorite. In this case, we are talking about the Seimchan meteorite. Using the neutron tomography method, scientists were able to obtain valuable scientific information about the composition and spatial distribution of matter in this object without destroying the fragment itself.

A meteorite, part of which was examined in the laboratory, belongs to the class of pallasites - This is one of the rarest and most beautiful varieties of meteorites. The first pallasite found was the Pallasov meteorite. He was found in the area of ​​the city of Krasnoyarsk in 1749. Described the object P.S. Pallas in 1773 ode. In 1794, E. Khladni defined a meteorite as an extraterrestrial object.

Pallasites are a separate class in the type of iron-stone meteorites. They are an iron-nickel base interspersed with olivine crystals. The meteorite class was named in honor of Academician P.S. Pallas, who described meteorites such as native iron, not realizing that he was dealing with an extraterrestrial object (which, of course, is excusable for the 18th century). The composition of pallasites is iron (80-90%) and nickel (3-20%). Also part of the pallasites are olivines, which have a similar structure and composition. Compared to terrestrial samples, they are depleted in calcium and nickel.


Treated Pallasite Fragment with Olivine Fragments

Physicists from the university’s laboratory examined a fragment of a meteorite found near the village of Seymchan (Magadan Region) in 1964. According to scientists, this fragment has all types of morphology of olivine grains, as well as large metal areas. At the moment, several fragments of the Now meteorite are known. Two of them, weighing 272 and 51 kg, were discovered in the 1960s. Experts found another chip weighing about 50 kg in 2004.

“Such rare space objects require special non-destructive methods of scientific research. Thus, you can get quite a lot of information about their structure. The neutron tomography method gave unique results, ”said in an interview. Izvestia Sergei Kichanov, Senior Researcher at the LNP JINR

The meteorite was studied in Dubna using an IBR-2 pulsed high-flux fast neutron reactor. Compared with x-ray radiation, neutron allows you to penetrate deeper into the studied object. And the resulting images make it possible to find out information about the internal structure of the fragment and the distribution of inhomogeneities.

Differences in the interaction of neutrons with an iron-nickel alloy and olivine grains gave scientists the opportunity to create a contrasting three-dimensional picture of the meteorite components. They were able to study the distribution of nickel in the so-called metal matrix, determine the length of the metal “veins”, and examine the distribution of olivine grains in size and volume.

“Based on the results of our research, a scientific publication was sent to the international journal Meteoritics & Planetary Science, which should draw the attention of the international meteorite community to structural studies of the Seymchan meteorite,” said Sergey Kichanov.

Colleagues of physicists from the Joint Institute for Nuclear Research agree that the object selected for study is very interesting for science. “These are interesting objects. They are also called Pallas iron in honor of Academician Pallas, who found the first iron-stone meteorite in the vicinity of Krasnoyarsk. Seymchan is perhaps the most famous of them, ”said Faina Rubleva, scientific director of the Moscow Planetarium.

“I can confirm that the object of study is quite interesting, and the neutron tomography method is standard. It is widely used for a wide variety of objects, including geological samples, ”commented the research head of the MIPT Laboratory of Applied Infrared Spectroscopy, astrophysicist Alexander Rodin. In his opinion, the results of the study will help to understand the processes of the formation of pallasites from asteroids.