Ancient asteroid grains provide insight into the evolution of our solar system

The UK’s national synchrotron facility, Diamond Light Source, was used by a large international collaboration to study grains collected from a near-Earth asteroid to improve our understanding of the evolution of our solar system.

Researchers at the University of Leicester brought a fragment of the Ryugu asteroid to the I14 beamline of Diamond’s Nanoprobe, where a special technique called near-edge X-ray absorption spectroscopy (XANES) was used to map the chemical states of the elements. inside the asteroid material, to examine its composition in great detail. The team also studied asteroid grains using an electron microscope at Diamond’s Electron Physical Sciences Imaging Center (ePSIC).

Julia Parker is the Lead Beamline Scientist for I14 at Diamond. She said: “The X-ray nanoprobe allows scientists to examine the chemical structure of their samples at micron to nano length scales, which is complemented by the nano to atomic resolution of the images in ePSIC. It is very exciting to be able to contribute to the understanding of these unique samples and to work with the Leicester team to demonstrate how beamline techniques, and correlatively ePSIC, can benefit future sample return missions.”

The data collected at Diamond contributed to a larger study of space weathering signatures on the asteroid. The pristine asteroid samples allowed the collaborators to explore how space weathering can alter the physical and chemical composition of the surface of carbonaceous asteroids like Ryugu.

The researchers found that Ryugu’s surface is dehydrated and that space weathering is likely to be responsible. The study findings, published today in Nature Astronomy, have led the authors to conclude that asteroids that appear dry on the surface may be rich in water, which could necessitate a revision of our understanding of the abundance of asteroid types. and their formation history. asteroid belt.

Ryugu is a near-Earth asteroid, about 900 meters in diameter, first discovered in 1999 within the asteroid belt between Mars and Jupiter. It is named after the underwater palace of the Dragon God in Japanese mythology. In 2014, the Japanese state space agency JAXA launched Hayabusa2, an asteroid sample return mission, to rendezvous with the Ryugu asteroid and collect samples of material from its surface and subsurface. The spacecraft returned to Earth in 2020, releasing a capsule containing valuable fragments of the asteroid. These small samples were distributed to laboratories around the world for scientific study, including the University of Leicester’s School of Physics and Astronomy and the Space Park, where John Bridges, one of the paper’s authors, is Professor of Planetary Sciences.

John said: “This unique mission to collect samples of the most primitive and carbonaceous building blocks in the Solar System requires the most detailed microscopy in the world, and that is why JAXA and the Fine Grain Mineralogy team wanted us to analyze samples at Diamond’s X-ray nanoprobe beam line We helped reveal the nature of space weathering on this asteroid with micrometeorite impacts and the solar wind creating dehydrated serpentine minerals, and an associated reduction of oxidized Fe3+ to more reduced Fe2+.

It is important to accumulate experience in the study of samples returned from asteroids, as in the Hayabusa2 mission, because soon there will be new samples from other types of asteroids, the Moon and within the next 10 years Mars, returned to Earth. The UK community will be able to perform some of the critical analysis thanks to our facilities at Diamond and the electron microscopes at ePSIC.”

The Ryugu building blocks are remnants of interactions between water, minerals, and organic compounds in the early Solar System before the formation of Earth. Understanding the composition of asteroids can help explain how the early solar system developed and, subsequently, how Earth formed. They may even help explain how life arose on Earth, as asteroids are thought to have brought much of the planet’s water, as well as organic compounds such as amino acids, which provide the building blocks from which all life is built. human life. The information being collected from these small asteroid samples will help us better understand the origin of not only planets and stars, but also life itself. Whether it’s asteroid fragments, ancient paintings or unknown virus structures, at the synchrotron, scientists can study their samples using a machine that is 10,000 times more powerful than a traditional microscope.

Based on research published in Nature Astronomy: ‘A space-worn dehydrated skin covering Ryugu’s hydrated interior‘ on December 19, 2022 at 4:00 p.m. (London time), on December 19, 2022 at 11:00 a.m. (US Eastern Time). DOI: 10.1038/s41550-022-01841-6

For more information, please contact Diamond Communications: Lorna Campbell +44 7836 625999 or Isabelle Boscaro-Clarke +44 1235 778130

Diamond Light Source: www.diamond.ac.uk Twitter: @DiamondLightSou

Diamond Light Source – Works like a giant microscope, harnessing the power of electrons to produce brilliant light that scientists can use to study anything from fossils to jet engines to viruses and vaccines. The machine accelerates electrons to near-light speeds so that they emit light 10 billion times brighter than the sun. These bright rays then head toward laboratories known as “beam lines.” Here, scientists use light to study a wide range of topics, from new drugs and disease treatments to innovative engineering and cutting-edge technology. Whether it’s fragments of ancient paintings or unknown virus structures, in the synchrotron, scientists can study their samples using a machine that is 10,000 times more powerful than a traditional microscope.

Astrobiology