The researchers hypothesized that the main body was later destroyed, losing most of its water and if the debris formed the modern asteroid Ryugu.

Why do scientists study meteorites?

Studies of meteorites that have fallen to Earth are important for understanding the properties of parent asteroids. An important role in establishing the connection between meteorites and asteroids is played by the data of automated instruments, as well as laboratory studies of the soil of asteroids mined by them. In particular, the material he extracted from the Hayabusa station and the Itokawa asteroid helped determine that S-type asteroids are composed of a substance that corresponds to normal chondrite meteorites.

Quest to Ryuga

Hayabusa-2’s target was the near-Earth asteroid Ryugu. In December 2020, the station delivered two samples to Earth weighing a total of 5.4 grams. The task of the device was to establish the relationship between C-type asteroids and carbon chondrite meteorites.

Ryuga’s observations helped determine that it was darker than any other meteorite type and contained phyllosilicates. In general, carbon chondrites can be considered similar to Ryug, but additional results of laboratory analyzes of soil samples of the asteroid brought to Earth are needed to explain the differences in the properties of the asteroid and meteorite.

Ryuga samples delivered to Earth / Science of Photography, 2022

A team of planetologists led by Tetsuya Yokoyama of the Tokyo Institute of Technology has published the results of petrographic, isotope, mineral and chemical composition studies of 95 milligrams of Ryuga rocks using scanning electron microscopy, ion mass spectrometry, thermal ionization mass spectrometry and isotope. mass spectrometry and fluorination and X-ray fluorescence analysis.

What scientists discovered

In this study, samples of A0107, A0040, A0058, A0094 collected from the Ryuga surface and C0108 collected from the near-surface region of the asteroid were examined.

Ryuga specimens are a mixture of small phyllosilicate mineral grains (mainly serpentine and saponite) and large grains dominated by carbonates (dolomite, brainerite, calcite), magnetite, and sulphides (pyrrhotite, pentlandite, cubanite). Calcium and aluminum (CAI) inclusions, or chondra, found in most chondrite meteorites were found in the asteroid’s material. Anhydrous silicates such as olivine and pyroxene are common in chondrites, but very rare in Ryuga specimens with grains smaller than 10 micrometers in diameter. No metal particles were detected.

The scientists did not find systematic differences in chemical composition between samples from the two different soil sampling sites, only differences due to small-scale heterogeneity of the samples. The high volatile element content in Ryug’s samples indicates that the asteroid is close to meteorites such as Cl-chondrites, but the hydrogen and oxygen content in Ryug’s samples is greatly reduced compared to Cl-chondrites, which can be interpreted as dehydration by heating.

The mass ratios of the titanium and chromium isotopes for the Ryug samples are similar to those for the CB and CI chondrites. However, sulfates and ferrihydrite, commonly observed in CI chondrites, were not detected in the studied Ryug samples.

History of Ryuga

Overall, the petrology and mineralogy of the asteroid matter is most similar to the group of CI-chondrite-type chondrite meteorites represented by the Yvonne meteorite. It is assumed that the primary minerals in Ryuga were exposed to liquid water in the body of the asteroid at a temperature of about 37 degrees. This happened 5.2 million years after the first solids (CAI inclusions) formed in the solar system. In the future, most of the water was lost, most likely after the destruction of the main body and the formation of the modern Ryuga in the form of “rubble piles”. The paternal body of Ryuga was probably closely related to the paternal body (or bodies) of the CI-chondrites and formed 2-4 million years after the solar system formed from anhydrous dust and ice.