Vestiges of the Early Solar System in Ryugu Asteroid

Samples returned to Earth from the asteroid Ryugu, analyzed in part at the Advanced Light Source (ALS), revealed that the building blocks of life formed 4.6 billions years ago in the extreme cold of space, followed by reaction with water.

The dark, coal-like organic matter in the carbonaceous asteroid could have contributed to the formation of habitable planetary environments.

In 2014, the Japan Aerospace Exploration Agency (JAXA) launched the Hayabusa2 spacecraft. Its mission: to collect and return samples from the near-Earth asteroid, Ryugu. Asteroids are excellent time capsules, preserving material sourced from the early solar system in pristine condition. With such samples, scientists aim to learn more about how extraterrestrial organic compounds were formed and modified, and whether this material could have eventually seeded life on Earth. Although meteorites can provide valuable information along these lines, they are subject to terrestrial weathering and other contamination from a planet teeming with life.

Hayabusa2 returned to Earth in 2020 to drop off a capsule containing about 5 grams of extraterrestrial material. The spacecraft then left Earth orbit for an extended mission to a smaller asteroid, called 1998 KY26. The samples it left behind were carefully curated and distributed to teams around the world for study.

In the portion of the sample analysis described here, an international team of 130 researchers, led by Hikaru Yabuta at Hiroshima University, received a share of the irreplaceable Ryugu particles for studies of their organic (carbon-based) content. They examined intact Ryugu grains and insoluble carbonaceous residues isolated by acid treatment.

At ALS Beamline, the researchers used scanning transmission x-ray microscopy (STXM) to identify discrete grains of organic material (about 200 nm in size) for further examination by x-ray absorption near-edge structure (XANES) spectroscopy. The beamline enables the acquisition of elemental maps and functional group compositions in submicron-sized sample areas with a spatial resolution below 30 nm.

Read more on the ALS website

Image: Artwork showing the Hayabusa2 spacecraft retrieving a sample from the surface of asteroid Ryugu

Credit: Akihiro Ikeshita

New techniques available at SOLARIS synchrotron

From 2022, National Synchroton Radiation Center SOLARIS provides access to two new research techniques. Access to the Scanning Transmission X-ray Microscope and X-ray Absorption Spectroscopy beamline optimized for measurements in the soft and tender energy range, will be possible in the next call for proposals, in March 2022.

Scanning transmission X-ray microscopy (STXM) is a method to obtain a microscopic image of the raster-scanned sample by detecting the transmission intensity of the focused X-rays. The STXM is one of the two end stations of the DEMETER beamline in NSRC SOLARIS. The operating principle of the STXM is scanning of the sample in the focus of the Fresnel zone plate, which for this device is the lens focusing X-rays. In the next step, the detector measures the intensity of the radiation passing through the sample and, on the basis of the intensity images recorded by the detector, it is possible to calculate the absorption X-ray radiation in a selected place of the tested system. The most important measurement mode in STXM is the so-called “image stack” – a series of images are collected as a function of photon energy to obtain a dataset with space (XY) and energy (E) dimensions. A local absorption spectrum can be obtained from the arbitrary region of interest at the image. It allows a detail chemical composition analysis of a measured sample. The source for the STXM end station is elliptically polarized undulator, which enables to cover the energy range from 100 to 2000 eV. The undulator allows measurements using linear, circular and elliptical polarization. Detailed information about the STXM end station you can find here:

X-ray Absorption Spectroscopy beamline – SOLABS is a bending magnet beamline dedicated to X-ray absorption spectroscopy (XAS) in the energy range from 1 keV to 15 keV. The beamline was especially designed for XAS measurements in the tender X-ray range, i.e., at the K absorption edges of important elements such as P, S, Si, Al and Mg. Besides, the energy range also includes K-edges of heavier elements up to Se, L-edges of elements up to Bi and some M-edges of elements including U, which allows investigation of a variety of highly relevant materials. Due to this straightforward concept without any optical components such as lenses or mirrors, SOLABS can be quickly aligned and easily operated.  At the beamline spectroscopic experiments in different measurement modes and with various sample environments are possible. XAS is a non-destructive, element-specific characterization method that can be applied to both crystalline and amorphous materials, liquids and samples in the gas phase. Detailed information about the SOLABS beamline and the features of its end station can be found here:

Agnieszka Cudek

The Head of Communication, SOLARIS National Synchrotron Radiation Centre

To apply for beamtime, please visit the SOLARIS website

Analysing asteroid Ryugu samples

The asteroid Ryugu samples brought back by JAXA’s asteroid explorer “Hayabusa2” in December 2020 are analyzed by six initial analysis teams for one year from June 2021. Among the initial analysis teams, the “Stone Material Analysis Team” and the “Organic Macromolecule Analysis Team” conducts their analysis at the Photon Factory, KEK.

It is thought that asteroids such as Ryugu may have brought water and organic matter to the Earth in the past. By integrating the results of each team’s analysis, we will be closer to solving the great mystery of how life came to be on the Earth.

Read more on the HAYABUSA2-IMSS website

Image : Primordial solar system.