A new study shows that about 70% of meteorites originate from at least three recent breakups of giant asteroids.
This is the artist’s impression of the asteroid as it breaks apart. Credit: NASA/JPL-California Institute of Technology.
A type of meteorite, commonly called a chondrite, accounts for about 80% of all meteorites that hit Earth, including those that were involved in the violent impact period about 466 million years ago that is thought to have started the Ice Age. Included.
Previous studies have demonstrated that approximately 70% of meteorites on Earth have compositions known as H and L chondrites.
Argon-argon dating of L-chondrite meteorites on Earth suggests that these samples may have originated from the catastrophic destruction of a single asteroid that experienced a supersonic impact approximately 470 million years ago. It turned out to be high.
In a new study, ESO and MIT researcher Dr. Michael Marcet and colleagues compiled spectroscopic data from asteroids in the main belt between Mars and Jupiter.
They found that a group of asteroids known as the Massalia family is very similar in composition to L-chondrite meteorites on Earth.
Through computer modeling, they propose that an impact event about 450 million years ago destroyed an L-chondrite asteroid, forming the Massalia family and providing debris that fueled the influx of meteorites.
In a second study, Charles University researcher Miroslav Broju and his colleagues found that the current influx of H and L chondrite meteorites was likely caused by three recent breakups.
These events occurred about 5.8, 7.6 and 40 million years ago and involved the destruction of asteroids over 30 km (18.6 miles) in diameter.
More specifically, they suggest that the impact formation of the relatively young Karin and Coronis asteroid families and a second impact event (about 40 million years ago) in the older Massalia asteroids are currently falling to Earth. I guessed that explained most of the meteorites.
In a third follow-up study, Dr. Brož and co-authors extended their approach to all meteorite families, identifying the major sources of carbonaceous chondrites and achondrites, in addition to those from the Moon, Mars, and Vesta. revealed.
“Our discovery provides insight into the mystery of where the most common meteorites that have ever hit Earth came from and how those impacts shaped Earth’s history.” ,” the researchers said.
The results are published in three papers in Nature and Astronomy & Astrophysics.
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M. Marcet et al. 2024. Massalia asteroid family as the origin of ordinary L chondrites. Nature 634, 561-565; doi: 10.1038/s41586-024-08007-6
M. Brož et al. 2024. Young asteroids as the main source of meteorites. Nature 634, 566-571; doi: 10.1038/s41586-024-08006-7
M. Brož et al. 2024. Source region of carbonaceous meteorites and near-Earth objects. A&A 689, A183; doi: 10.1051/0004-6361/202450532
