Rochester researchers uncover key clues about the solar system's history

December 04, 2020

In a new paper published in the journal Nature Communications Earth and Environment, researchers at the University of Rochester were able to use magnetism to determine, for the first time, when carbonaceous chondrite asteroids--asteroids that are rich in water and amino acids--first arrived in the inner solar system. The research provides data that helps inform scientists about the early origins of the solar system and why some planets, such as Earth, became habitable and were able to sustain conditions conducive for life, while other planets, such as Mars, did not.

The research also gives scientists data that can be applied to the discovery of new exoplanets.

"There is special interest in defining this history--in reference to the huge number of exoplanet discoveries--to deduce whether events might have been similar or different in exo-solar systems," says John Tarduno, the William R. Kenan, Jr., Professor in the Department of Earth and Environmental Sciences and dean of research for Arts, Sciences & Engineering at Rochester. "This is another component of the search for other habitable planets."

SOLVING A PARADOX USING A METEORITE IN MEXICO

Some meteorites are pieces of debris from outer space objects such as asteroids. After breaking apart from their "parent bodies," these pieces are able to survive passing through the atmosphere and eventually hit the surface of a planet or moon.

Studying the magnetization of meteorites can give researchers a better idea of when the objects formed and where they were located early in the solar system's history.

"We realized several years ago that we could use the magnetism of meteorites derived from asteroids to determine how far these meteorites were from the sun when their magnetic minerals formed," Tarduno says.

In order to learn more about the origin of meteorites and their parent bodies, Tarduno and the researchers studied magnetic data collected from the Allende meteorite, which fell to Earth and landed in Mexico in 1969. The Allende meteorite is the largest carbonaceous chondrite meteorite found on Earth and contains minerals--calcium-aluminum inclusions--that are thought to be the first solids formed in the solar system. It is one of the most studied meteorites and was considered for decades to be the classic example of a meteorite from a primitive asteroid parent body.

In order to determine when the objects formed and where they were located, the researchers first had to address a paradox about meteorites that was confounding the scientific community: how did the meteorites gain magnetization?

Recently, a controversy arose when some researchers proposed that carbonaceous chondrite meteorites like Allende had been magnetized by a core dynamo, like that of Earth. Earth is known as a differentiated body because it has a crust, mantle, and core that are separated by composition and density. Early in their history, planetary bodies can gain enough heat so that there is widespread melting and the dense material--iron--sinks to the center.

New experiments by Rochester graduate student Tim O'Brien, the first author of the paper, found that magnetic signals interpreted by prior researchers was not actually from a core. Instead, O'Brien found, the magnetism is a property of Allende's unusual magnetic minerals.

DETERMINING JUPITER'S ROLE IN ASTEROID MIGRATION

Having solved this paradox, O'Brien was able to identify meteorites with other minerals that could faithfully record early solar system magnetizations.

Tarduno's magnetics group then combined this work with theoretical work from Eric Blackman, a professor of physics and astronomy, and computer simulations led by graduate student Atma Anand and Jonathan Carroll-Nellenback, a computational scientist at Rochester's Laboratory for Laser Energetics. These simulations showed that solar winds draped around early solar system bodies and it was this solar wind that magnetized the bodies.

Using these simulations and data, the researchers determined that the parent asteroids from which carbonaceous chondrite meteorites broke off arrived in the Asteroid Belt from the outer solar system about 4,562 million years ago, within the first five million years of solar system history.

Tarduno says the analyses and modeling offers more support for the so-called grand tack theory of the motion of Jupiter. While scientists once thought planets and other planetary bodies formed from dust and gas in an orderly distance from the sun, today scientists realize that the gravitational forces associated with giant planets--such as Jupiter and Saturn--can drive the formation and migration of planetary bodies and asteroids. The grand tack theory suggests that asteroids were separated by the gravitational forces of the giant planet Jupiter, whose subsequent migration then mixed the two asteroid groups.

He adds, "This early motion of carbonaceous chondrite asteroids sets the stage for further scattering of water-rich bodies--potentially to Earth--later in the development of the solar system, and it may be a pattern common to exoplanet systems."
-end-


University of Rochester

Related Solar System Articles from Brightsurf:

Ultraviolet shines light on origins of the solar system
In the search to discover the origins of our solar system, an international team of researchers, including planetary scientist and cosmochemist James Lyons of Arizona State University, has compared the composition of the sun to the composition of the most ancient materials that formed in our solar system: refractory inclusions in unmetamorphosed meteorites.

Second alignment plane of solar system discovered
A study of comet motions indicates that the Solar System has a second alignment plane.

Pressure runs high at edge of solar system
Out at the boundary of our solar system, pressure runs high.

What a dying star's ashes tell us about the birth of our solar system
A UA-led team of researchers discovered a dust grain forged in a stellar explosion before our solar system was born.

What scientists found after sifting through dust in the solar system
Two recent studies report discoveries of dust rings in the inner solar system: a dust ring at Mercury's orbit, and a group of never-before-detected asteroids co-orbiting with Venus, supplying the dust in Venus' orbit.

Discovered: The most-distant solar system object ever observed
A team of astronomers has discovered the most-distant body ever observed in our solar system.

Discovery of the first body in the Solar System with an extrasolar origin
Asteroid 2015 BZ509 is the very first object in the Solar System shown to have an extrasolar origin.

First interstellar immigrant discovered in the solar system
A new study has discovered the first known permanent immigrant to our solar system.

A star disturbed the comets of the solar system in prehistory
About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids.

Scientists detect comets outside our solar system
Scientists from MIT and other institutions, working closely with amateur astronomers, have spotted the dusty tails of six exocomets -- comets outside our solar system -- orbiting a faint star 800 light years from Earth.

Read More: Solar System News and Solar System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.