COLUMBIA, Md. and HOUSTON, Aug. 2, 2022 /PRNewswire/ — A recent study reports evidence of deformation of the oldest solids formed in our solar system resulting from nebular collisions. The results of this work suggest that these shocks may have been active and more widespread in the early solar system than previously thought. The study was published in Geochimica and Cosmochimica Acta.
Calcium-aluminum-rich inclusions (CAI) are millimeter to centimeter-sized objects hosted in early meteorites. They are the oldest solids to condense from nebular gas and therefore retain records of early chemical and physical processes. A recent study of a CAI from the chondrite NWA 5028 CR2 suggests that some CAIs may have experienced nebular shocks in early stages of the solar system’s history.
“CAIs are made up of high-temperature forming minerals rich in refractory elements such as calcium and aluminum. Radiometric dating of CAIs and their components suggests that the majority of these inclusions formed during the first million years of our solar system’s history and thereby preserve snapshots from the earliest events to the very beginning of our solar system,” says Prajkta Mane, lead author of the study and a scientist with the Space Research Association of Universities. at the Lunar and Planetary Institute.
“These CAIs represent, to our knowledge, the first solids that formed in the solar system. We believe they underwent large-scale transport in our first solar nebula and witnessed a range of physical and chemical processes during their lifetime. is the first to constrain time scales with physical shock wave treatment,” says Tom Zega, co-author of the study.
Coordinated analysis of a CAI hosted in carbonaceous chondrite revealed intensely distorted microstructures in melilite and spinel, suggesting it was shocked at high ambient temperature. Further time constraints on this event, imposed by short-lived 26Al-26Mg chronometry, revealed that the shock event occurred very early, within the first hundreds of thousands of years of recorded history. of the solar system. Nebular shock waves would be responsible for the fusion of chondrules, major chondritic components rich in ferromagnesian minerals. However, shock deformation in CAIs implies that nebular shocks may have been more frequent in the early solar system than previously thought. Numerous studies using light microscopy and transmission electron microscopy have reported that CAI melilite exhibits microstructures consistent with significant stress and strain, providing clues to their tortured past. The EBSD analytical technique provides a more complete and quantitative view of this deformation. “Microscopy techniques combined with isotopic analysis provide a holistic understanding of these events,” said study lead author Prajkta Mane.
The results of this work imply that nebular shocks were active in the solar system over a wide spatial extent, from 0.1 AU to beyond Jupiter. Moreover, these nebular shocks were active very early, at the beginning of the solar system. The astrophysical mechanisms behind these nebular shocks remain elusive, and further studies of early meteoritic components and samples returned from early asteroids, combined with astrophysical models, are needed to understand the extent of nebular shocks at the time. course of early planet formation.
This work was done in collaboration with the Lunar and Planetary Institute (USRA), Arizona State University, University of Arizona, and EDAX Ametek.
About the USRA
Founded in 1969, under the auspices of the National Academy of Sciences at the request of the United States government, the Universities Space Research Association (USRA) is a nonprofit corporation dedicated to advancing science, technology, and engineering related to space. The USRA operates scientific institutes and facilities and conducts other major research and educational programs. USRA engages the academic community and employs in-house scientific leadership, innovative research and development, and project management expertise. More information about the USRA is available at www.usra.edu.
The Lunar and Planetary Institute (LPI), operated by the Space Research Association of Universities, was established during the Apollo program in 1968 to foster international collaboration and serve as a repository for information gathered during the early years of the program spatial. Today, LPI is an intellectual leader in lunar and planetary science. The Institute serves as a scientific forum attracting world-class visiting scientists, postdoctoral fellows, students and resident experts; supports and serves the research community through newsletters, meetings, and other activities; collects and disseminates planetary data while facilitating community access to NASA science; and engages, excites and educates the public about space science and invests in the development of future generations of explorers. Research conducted at LPI supports NASA’s efforts to explore the solar system. More information about LPI is available at www.lpi.usra.edu.
Suraiya Farukhi, Ph.D.
Dr. Prajkta Mane
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SOURCE Space Research Association of Universities