Understanding the formation of dust grains in interstellar gas can provide astronomers with valuable information and help materials scientists create useful nanoparticles. Hokkaido University researchers and colleagues from Japan and Germany have discovered new information about the origin of interstellar dust particles through laboratory and rocket studies. Findings published in the journal Science AdvancesIt could give scientists a deeper understanding of the formation process and lead to the development of more efficient and environmentally friendly methods of forming nanoparticles with practical applications.

These “pre-solar” grains can be found in meteorites that have fallen to Earth, allowing laboratory studies to reveal possible formation pathways.

“The shapes of snowflakes provide information about the temperature and humidity of the upper atmosphere, as well as the properties of pre-solar grains in meteorites that limit the stellar output environment in which they could have formed,” explains Yuki Kimura of Hokkaido. set. Unfortunately, it has proven difficult to identify possible environments for the formation of grains consisting of a titanium carbide core and a surrounding graphite carbon shell.

A better understanding of the environment around stars in which grains may have formed is crucial to learning more about the interstellar medium in general. This, in turn, can help clarify how stars develop and how the materials around them become the building blocks for planets.

The structure of the grains suggests that the titanium carbide core formed first and was then covered by a thick layer of carbon in the more distant regions of gas escaping from stars that formed before the Sun.

Guided by theoretical work on grain nucleation (the formation of grains from small original particles), the team investigated conditions that could reproduce grain formation in laboratory simulation studies. This work was supported by experiments conducted during periods of microgravity during the flights of suborbital rockets.

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The results also brought some surprises. They suggest that the grains most likely form in what the researchers call a nonclassical nucleation pathway: a sequence of three distinct steps not predicted by conventional theories. First, carbon forms small, uniform nuclei; the titanium then settles on top of these carbon cores with the formation of titanium carbide-containing carbon particles; Finally, thousands of these tiny particles combine to form one.

“We also hypothesize that the properties of other pre-solar and solar particles formed in later phases of the Solar System can be accurately explained by non-classical nucleation pathways such as those proposed in our work,” Kimura said.

The research could help understand distant astronomical events, including giant stars, nascent planetary systems, and the atmospheres of planets in alien solar systems around other stars. But it could also help scientists on Earth gain better control over the nanoparticles they’re investigating for use in many fields, including solar energy, chemical catalysis, sensors and nanomedicine. Therefore, the potential implications of studying tiny grains in meteorites stretch as far back as we can imagine from the future of Earth industry.