Scientists use a new method of analysis to discover the mysterious origin of the grains of an ancient meteorite dating back to before the formation of the solar system and its information Interpret.
The oldest material discovered on Earth may now give us clues to prehistoric history. Humans now have 7 billion-year-old pieces of ancient meteorites that are older than the solar system and are known as "presolar grains."
These grains in ancient stars that They died before our Sun was born, formed, but there are still similar stars in the universe, and analyzing the information stored in meteorites can provide an interesting insight into the chemistry of this type of star.
They were to analyze pre-solar grains in meteorites, but now Nan Liu, an assistant professor of physics at the University of Washington, has published a new article published in the Astrophysical Journal Letters on October 12 (October 24). The initial study of these grains was very inaccurate.
Liu and his team provided examples of "Murchison Meteorites", a total of 100 kg space rocks, that were erected in 1969. The Australian city of Marquis landed, surveyed. Scientists who have previously studied these meteorites quickly realized that the meteorites fell with great luck, but not just because a large piece of it landed on the roof of a warehouse without harming anyone.
A piece of Markison meteorite
- Rare meteorites can reveal the
secrets of the origin of life on Earth . "Scientists know from
previous research that these grains belong to the pre-natal solar
system because their chemical composition is different." "These
grains are made of silicon carbide, that is, silicon and carbon
atoms, but these "Composition does not form naturally in our solar
system because there is so much oxygen around us that all of these
carbon atoms react with oxygen to produce carbon dioxide
molecules." Are bright red giants whose atmosphere has more carbon
than oxygen. But to prove this theory, scientists need to know
whether the composition of certain isotopes in meteorite grains is
consistent with carbon stars. Isotopes are actually types of a
chemical element that differ in the number of neutrons in the
nucleus. While some isotopes are common in the solar system, others
are formed only within certain types of stars.
Nebulae with strong dust currents, such as the Egg Nebula, can be the source of pre-solar grains.
Credit: NASA, W. Sparks (STScI) and R. Sahai (JPL). Inset: SiC grain with ~ 8 micrometers in its longest dimension. Inset image courtesy of Janana N. vila.
Liu said: The isotopic ratios of these grains are very different from what we see in the solar system. For example, in solar system objects, the ratio of carbon 12 to carbon 13 is about 89. But these pre-solar grains have a carbon-12 to carbon 13 ratio of 2 to 200, which is the result of fusion reactions in their parent stars. Interestingly, the same is true of the isotopes of nitrogen, aluminum, and magnesium. . Something that researchers have not yet come to convincing conclusions about. One reason may be that these stars were not the site of the formation of these grains, but according to Liu, the explanation could be much simpler.
He said: Showed in those grains. But I thought there might be a problem with the review method. "These grains have spent hundreds of millions of years in the interstellar environment and billions of years in our solar system, and as a result their surface may have absorbed new matter." This means that in previous studies, scientists may have measured younger impurities on the surface instead of pre-solar grains themselves.
So Liu et al. The seeds stick, they designed. As part of this technique, they first dissolved Marquison meteorite fragments in acid to leave only silicon carbide grains. The grains were then bombarded with cesium and oxygen ions to remove any material that may be due to the younger components of the meteorite.
Silicon Carbide Spectroscopy in Ancient Meteorite Grains
Credit: Nan Liu
Finally, this research team, Performed spectroscopic measurements of grain isotope composition. According to Liu, the results are much closer to the carbon star observation data. This confirmed Liu's initial skepticism about the inaccuracy of the previous study, and showed that not only were the grains likely to have come from carbon stars, but that they could be used to help scientists understand these types of stars. "The new isotopic data obtained in this study are exciting for stellar physicists and nuclear astrophysicists like me," said Maurizio Busso, another author of the study from the University of Perugia in Italy. . In fact, the strange isotopic nitrogen ratios of pre-solar silicon carbide grains have been very challenging over the past two decades. The new data explains the difference between what first existed in the pre-star star grains and later joined it, thus solving an old conundrum.
Describes how carbon stars produce aluminum in their cores. However, despite the good results, he emphasizes that the findings of this study should be confirmed by further research.
- A falling meteor could land on a giant asteroid Cover
Cover Photo: Image of pre-solar grains of Marquison meteor shower by electron microscope
Credit: NASA, Nan Liu, Andrew Davis