Scientists recreate the journey of a dust grain out of the solar system

In time The birth of our solar system about 4.5 billion years ago, our sun was not the blazing fireball we know today, but a rotating disk of gas and dust known as the protoplanetary disk or solar nebula that began forming and forming the planets that would orbit it.

To take us on an unprecedented time journey into that pristine environment, A research team led by the University of Arizona was able to reconstruct unprecedented details of the history of a dust grain that formed at that moment, In an effort to provide information on the basic processes that underlie the formation of planetary systems, many of which are still shrouded in mystery.

to perform the search, The scientists developed their work in which they combined quantum mechanics and thermodynamics to simulate the conditions the grains experienced during their formation. Comparing the model’s predictions with a highly detailed analysis of the sample’s chemical composition and crystal structure, along with a model of how matter is transported in the solar nebula, revealed clues about the grain’s flight and environmental conditions, which formed along the way.

Our solar system began as a rotating disk of gas and dust 4.567 million years ago. Understanding the thermodynamic landscape and evolution of this disk remains a major challenge in planetary science, as properties of the materials from which planets formed within this cloud have been determined. This understanding requires a robust quantitative model that includes detailed information about the pressures and temperatures within the disk and how they vary over time and place. Important limitations on these parameters come from the examination of materials within meteorites. The experts responsible for the research explained that there is a record of their formation history within their micro- and atomic structures, which was controlled by the collective array of environments they were exposed to.”

The grains in question analyzed in the study are one of several inclusions known as Inclusions rich in calcium and aluminum, or CAI, were detected in a sample of the Allende meteorite, which fell over the Mexican state of Chihuahua in 1969. CAIs are of particular interest because they are believed to be among the first solids to form in the Solar System more than 4.5 billion years ago. Similar to the way stamps in a passport tell a story about a traveler’s journey and stops along the way, the micro- and atomic-scale structures of the samples establish a record of their formation history, which was controlled by the collective environments in which they were. was exposed.

As far as we know, our article is the first of its kind It tells an origin story that provides clues to possible processes that occurred on the astronomical distance scale with what we see in our sample on the atomic distance scale,” said Tom Zega, a professor at the University of Arizona’s Lunar and Planetary Laboratory and first author of the research paper, published In the specialized magazine Journal of Planetary Science.

Ziga and his team The composition of the impurities embedded in the meteorite was analyzed using state-of-the-art scanning atomic resolution electron microscopes, one at the Kuiper Materials Imaging and Characterization Facility at the University of Arizona, and his microscope brother located at the Hitachi factory in Hitachinaka, Japan, by which It found that inclusions consist primarily of mineral types known as spinel and perovskite, which are also found in rocks on Earth and are being studied as candidate materials for applications such as microelectronics and photovoltaics.

These similar types of solids occur in other types of meteorites known as carbonaceous chondrites, which are of particular interest to planetary scientists as they are known to be remnants of the formation of the Solar System and contain organic molecules, including those that may have provided the raw materials. materials for life. Careful analysis of the spatial arrangement of the atoms allowed the team to study the composition of the underlying crystal structures in great detail.. To the team’s surprise, some of the findings were at odds with current theories about the physical processes believed to be active within the protoplanetary disks, prompting them to dig deeper.

“We don’t know what chemical pathways led to the origin of these inclusions. Nature is our beaker, and this experience took place billions of years before our existence, in a totally alien environment.Said Ziga, who explained that the team set out to “reverse-engineer” the formation of extraterrestrial samples by designing new models that simulate the complex chemical processes, to which the samples would undergo within a protoplanetary disk.

“Such models require a close convergence of expertise spanning the fields of planetary science, materials science, mineral science, and microscopy. Which we set out to do,” added Krishna Muralidaran, co-author of the study and associate professor in the Arizona Department of Materials Science and Engineering. Based on the data the authors were able to extract from their samples, they concluded that the particle formed in a region of the protoplanetary disk not far away. about where Earth is now, and then they made a trip closer to the sun, where it was gradually hotter., only to later reverse course and wash in cooler places away from the young sun. Eventually, it joined an asteroid, and then split into pieces. Some of these were captured Slashes by Earth’s gravity and fell like meteorites in Mexico.

The samples for this study were taken from within a meteorite and are considered primitive, that is, they are not affected by environmental influences. It is believed that this early material has not undergone any significant change since it was first formed over 4.5 billion years ago, which is a rare occurrence.. It remains to be seen if similar objects are produced on the asteroid Bennu, samples of which will be returned to Earth by the OSIRIS-REx mission led by Osirizona in 2023. Until then, scientists rely on samples falling to Earth via meteorites. “This material is the only record we have of what happened 4.567 billion years ago in the solar nebula,” said Dr. Venkat Manga, co-author of the research and assistant research professor in the Arizona Department of Materials Science and Engineering. “Being able to observe the microstructure of our sample at various scales, right down to the length of individual atoms, is like opening a book.”

The authors added that such studies could bring planetary scientists one step closer to a “great model of planet formation”: Detailed understanding of the matter that moves around the disk, its components, and how the sun and planets are born. Powerful radio telescopes such as the Atacama Large Millimeter/ Submillimeter Array, or ALMA, in Chile now allow astronomers to view star systems as they evolve, Ziga said.

“Maybe at some point we can look at the records in evolution, and then we can really compare our data across disciplines and start answering some of these really important questions.Ziga said. “Do these dust particles form where we think they formed in our solar system? Are they common to all star systems? Should we expect the pattern we see in our solar system – rocky planets near the central star and distant gas giants – in all systems?”

“It’s a really fun time to be a scientist when these fields are developing so quickly,” he added. “And it is amazing to be in an institution where researchers can form an interdisciplinary collaboration between the major departments of astronomy, planetary sciences and materials at the same university.”

Read on: