A group of Japanese researchers found traces of carbon dioxide-rich water in the inclusions of a primitive meteorite, bringing new clues to the formation of these bodies and the solar system. The study is published in Science Advances
Water – the blue gold on which our existence depends – is not a rarity in the Solar System. Indeed, it is found almost everywhere: on Mars, on Saturn, in comets, on Enceladus, on Europa and, of course, on our dear planet Earth. Water, an altogether simple molecule that unites hydrogen, the most common atom in the universe, and oxygen, which is produced in abundance by stellar processes, probably plays an important role in the formation of planetary systems.
Water is also present in meteorites , often in the form of hydrated minerals : crystalline solids that have incorporated their molecules. But water can also be present in the crystals in the form of inclusions : small pockets inside the rock that contain water in a fluid state.
These inclusions have been found in the past within some ordinary chondrites , the most common type of meteorite, but a research team led by Akira Tsuchiyama of Ritsumeikan University in Kyoto also found them inside a meteorite belonging to the class of carbonaceous chondrites . These meteorites are rarer than ordinary ones and come from much older bodies (such as the asteroids Ryugu and Bennu ), which probably date back to the origin of the Solar System and can therefore tell us something of those remote times.
The research was conducted on fragments of Sutter’s Mill , a meteorite that fell in California in 2012 whose origin is probably to be traced back to an asteroid 4.6 billion years old, shortly after the formation of the same planetary system. Published in Science Advances , the study was conducted with microscopy techniques that made it possible to identify inclusions of water at the nanoscale within calcite crystals . It is not, however, water smooth , but containing at least 15 per cent of carbon dioxide – more than what we find sparkling water.
This discovery has interesting implications for our knowledge of the history of the solar system. The presence of the inclusions in Sutter’s Mill is probably due to the formation of the parent body in an area rich in ice water and carbon dioxide. And this also means that the region in which it formed must have been quite cold, beyond the orbit of Jupiter . The asteroid must then have been transported, through gravitational interaction with other planets and asteroidal dynamics processes, to the inner solar system, where its fragments may have fallen to Earth. It would therefore be an experimental proof of the mechanisms of transport of material between the kingdom of the giant planets and that of the rocky planets.
“Researchers know that liquid water can remain within crystal inclusions,” Tsuchiyama says. “The result shows that our team is able to detect them within a 4.6 billion-year-old mineral.”
Featured image: The nano-inclusions of water within the calcite crystals of the Sutter’s Mill meteorite. Credits: Tsuchiyama et al., 2021
To know more
- Read the article in Science Advances “ Discovery of primitive CO2-bearing fluid in an aqueously altered carbonaceous chondrite ”, by A. Tsuchiyama, A. Miyake, S. Okuzumi, A. Kitayama, J. Kawano, K. Uesugi, A. Takeuchi, T. Nakano and M. Zolensky
Provided by INAF