(ORDO NEWS) — Laboratory and rocket studies have provided new insights into how interstellar dust particles originated before the formation of the solar system.
The results of the study, published by Hokkaido University scientists and colleagues in the journal Science Advances, could also help create nanoparticles with beneficial properties in the most efficient and environmentally friendly way.
Pre-solar grains can be found in meteorites that fall to Earth. Scientists are conducting laboratory studies, studying the possible ways of formation of these grains.
“Just as the shape of snowflakes provides information about the temperature and humidity of the upper atmosphere, the characteristics of pre-solar grains in meteorites limit the outflow environment in which they could form,” explains Yuki Kimura of the Hokkaido University team.
However, it turned out to be quite difficult to determine the conditions for the formation of grains with a titanium carbide core and an outer carbon shell.
The grain structure seems to suggest that a core of titanium carbide formed first, and then it was covered with a thick layer of carbon in the more distant regions of outflow of gas from stars.
The team studied the conditions under which grain formation can be recreated in the laboratory. Scientists were guided by theoretical studies on the origin of grains. This work was complemented by experiments carried out in microgravity during suborbital rocket flights.
The results produced several surprises. The scientists concluded that the grains formed as a result of three separate stages, not predicted by traditional theories. At first, carbon formed tiny uniform nuclei.
Titanium was then deposited on these carbon cores and carbon particles containing titanium carbide were formed. Finally, thousands of these small particles coalesced to form a grain.
“We also suggest that the characteristics of other types of presolar and solar grains that formed in the later stages of the solar system can be accurately explained by considering non-classical nucleation pathways, such as those proposed by our work,” Kimura concludes.
The study could help understand distant astronomical events, including giant stars, newly formed planetary systems, and the atmospheres of planets in alien systems.
This work could also help scientists better control the nanoparticles they are researching for use in nanomedicine, solar energy and sensors.
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