Nav: Home

Crystalline silica in meteorite brings scientists closer to understanding solar evolution

August 22, 2018

A team of researchers from Waseda University, the Graduate University for Advanced Studies, the University of Hawaii at Manoa, Harvard University, and the National Institute for Polar Research discovered silica mineral quartz in a primitive meteorite, becoming the first in the world to present direct evidence of silica condensation within the solar protoplanetary disk and coming a step closer to understanding solar formation and evolution.

Though previous infrared spectroscopic observations have suggested the existence of silica in young and newly formed T Tauri stars as well as in asymptotic giant branch (AGB) stars in their last phase of life, no evidence of gas-solid condensation of silica had actually been found in primitive meteorites from the early stages of our solar system.

In this study, the scientists studied the primitive meteorite Yamato-793261 (Y-793261), a carbonaceous chondrite collected from an ice field near the Yamato Mountains during the 20th Japan Antarctic Research Expedition in 1979.

"The degree of crystallinity of organic matter in Y-793261 shows that it did not undergo thermal metamorphism," explains Timothy Jay Fagan, professor of geochemistry at Waseda University. "This confirms that Y-793261 preserves minerals and textures of its nebular origin, providing us with records of the early solar system."

A major component of chondrites includes refractory inclusions, which formed at high temperatures and are the oldest solar system solids dated. Refractory inclusions can be subdivided into calcium-aluminum-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs). The research team found an AOA in Y-793261 containing typical AOA minerals and ultrarefractory (very high temperature) scandium- and zirconium-bearing minerals along with the quartz (which forms at comparatively lower temperature). "Such variety in minerals implies that the AOA condensed from nebular gas to solid over a wide temperature range from approximately 1500 - 900°C," Professor Fagan points out. "This aggregate is the first of its kind to be found in our solar system."

They also found that the quartz in the AOA has an oxygen isotopic composition close to the Sun's. This isotopic composition is typical of refractory inclusions in general, which indicates that refractory inclusions formed close to the protosun (approximately 0.1 AU, or 1/10 of the distance from the Earth to the Sun). The fact that the quartz in the Y-793261 shares this isotopic composition indicates that the quartz formed in the same setting in the solar nebula. However, silica condensation from solar nebula gas is hypothetically impossible if minerals and gas remain in equilibrium during condensation. This finding serves as evidence that the AOA formed from a rapidly cooling gas. As silica-poor minerals condensed from the gas, the gas changed composition, becoming more silica-rich, until the quartz became stable and crystallized.

Professor Fagan says that the origin of Y-793261 is most likely an astronomical object near 162173 Ryugu (commonly known as Ryugu), an asteroid named after a dragon's palace from an old Japanese folktale. Currently being investigated by the Japanese spacecraft Hayabusa 2, Ryugu may share the same properties as Y-793261 and potentially provide more records on the early solar system. "By combining ongoing research on meteorites with new results from Ryugu, we hope to better understand the thermal events and transfers of mass that occurred during the beginning stages of our solar system."

This study was published online in Proceeding of the National Academy of Sciences of the United States of America (PNAS) on July 2, 2018 (EST).
-end-
Reference

Title: First evidence for silica condensation within the solar protoplanetary disk
Authors: Mutsumi Komatsu, Timothy Fagan, Alexander Krot, Kazuhide Nagashima, Michail Petaev, Makoto Kimura, Akira Yamaguchi
Published online in Proceeding of the National Academy of Sciences of the United States of America (PNAS) on July 2, 2018 (EST)
DOI: 101073/pnas.1722265115
University news on this study

About Waseda University

Waseda University is a leading private, non-profit institution of higher education based in central Tokyo, enrolling over 50,000 students in the 13 undergraduate and 20 graduate schools. Founded in 1882, Waseda cherishes three guiding principles: academic independence, practical innovation and the education of enlightened citizens. Established to mold future leaders, Waseda continues to fulfill this mission, counting among its alumni seven prime ministers and countless other politicians, business leaders, journalists, diplomats, scholars, scientists, actors, writers, athletes and artists. The University is also number one in Japan in international activities, including the number of international students, and has the broadest range of degree programs fully taught in English.

Waseda University

Related Solar System Articles:

From rocks in Colorado, evidence of a 'chaotic solar system'
Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists from the University of Wisconsin-Madison and Northwestern University has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun.
Why are there different 'flavors' of iron around the Solar System?
New work from Carnegie's Stephen Elardo and Anat Shahar shows that interactions between iron and nickel under the extreme pressures and temperatures similar to a planetary interior can help scientists understand the period in our Solar System's youth when planets were forming and their cores were created.
Does our solar system have an undiscovered planet? You can help astronomers find out
ASU's Adam Schneider and colleagues are hunting for runaway worlds in the space between stars, and citizen scientists can join the search with a new NASA-funded website.
Rare meteorites challenge our understanding of the solar system
Researchers have discovered minerals from 43 meteorites that landed on Earth 470 million years ago.
New evidence on the formation of the solar system
International research involving a Monash University scientist is using new computer models and evidence from meteorites to show that a low-mass supernova triggered the formation of our solar system.
Planet Nine could spell doom for solar system
The solar system could be thrown into disaster when the sun dies if the mysterious 'Planet Nine' exists, according to research from the University of Warwick.
Theft behind Planet 9 in our solar system
Through a computer-simulated study, astronomers at Lund University in Sweden show that it is highly likely that the so-called Planet 9 is an exoplanet.
Studying the solar system with NASA's Webb Telescope
NASA's James Webb Space Telescope will look across vast distances to find the earliest stars and galaxies and study the atmospheres of mysterious worlds orbiting other stars.
'This solar system isn't big enough for the both of us.' -- Jupiter
It's like something out of an interplanetary chess game. Astrophysicists at the University of Toronto have found that a close encounter with Jupiter about four billion years ago may have resulted in another planet's ejection from the Solar System altogether.
IBEX sheds new light on solar system boundary
In 14 papers published in the October 2015 Astrophysical Journal Supplement, scientists present findings from NASA's Interstellar Boundary Explorer, or IBEX, mission providing the most definitive analyses, theories and results about local interstellar space to date.

Related Solar System Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#513 Dinosaur Tails
This week: dinosaurs! We're discussing dinosaur tails, bipedalism, paleontology public outreach, dinosaur MOOCs, and other neat dinosaur related things with Dr. Scott Persons from the University of Alberta, who is also the author of the book "Dinosaurs of the Alberta Badlands".