In the summer of 2021, a few milligrams of dust grains collected on the asteroid Ryugu more than 340 million kilometers from Earth, as part of the Japanese space mission Hayabusa-2, could be analyzed by various international laboratories. Among these laboratories, the SMIS beamline at SOLEIL.
Excitement of the discovery of these precious samples, first analyses… Follow the team of the Orsay “Institut d’Astrophysique Spatiale” at the SMIS beamline watching our new video.
Audio transcription
- We've got something here! Beautiful, magnificent…
- Get a better focus!
Voiceover
It is rare for grains of dust to arouse so much enthusiasm. But these grains took a long trip before coming to the SOLEIL synchrotron. These samples were taken on Ryugu asteroid, more than 340 million kilometres from Earth, and wandered through space for nearly two years before being retrieved in Australia in December 2020 by the Japanese Space Agency, in charge of the Hayabusa-2 mission.
Rosario Brunetto, Astrochemistry and Origins team leader (IAS/CNRS)
The mission gathered 5.5 grams of matter at two different places on the asteroid's surface. And part of these grains is currently being analysed at different laboratories around the world. A mission like this is really quite exceptional.
This grain is gorgeous, it's big…
Voiceover
This isn't the first time the teams at the Institut d’Astrophysique Spatiale and the SOLEIL synchrotron get to analyse extraterrestrial samples. With their understanding of meteorites, they have also had the opportunity to analyse dust from the Wild-2 comet and the Itokawa asteroid as part of the Hayabusa-1 mission. This time, the researchers are among the first analysing the dust.
Zélia Dionnet, postdoctoral fellow in physics (IAS/CNES)
Stefano Rubino, doctoral student in physics (IAS)
We're getting a bit of a preview because this is our first look at the grains, there is carbonaceous matter, there are some interesting things... it's not at all the same context. The last time we did this was for Hayabusa-1, it was part of call for proposals and the grains had already been circulating in the community for 5 years and were well-known. This didn't have the same feel to it at all...
Here, we are on the front lines of what is being discovered.
There is kind of a feeling of discovery, which is much more exciting.
Voiceover
This excitement can really be felt because the little grains they received are from a different kind of primitive asteroid.
Zahia Djouadi, physicist and lecturer (IAS/Université Paris-Saclay)
It was chosen because it is a small type-C asteroid, in other words it should contain organic matter. The idea behind it is actually to try and take a look at the origins of life.
Rosario Brunetto
On the question of bringing primitive water or organic matter to Earth – which could have helped with the emergence of life on Earth, actually we're not really sure – the question of the relative contribution between asteroids and comets is still open to debate. But we increasingly believe that asteroids played an important role in this history.
Alice Aléon-Toppani, geologist and lecturer (IAS/Université Paris-Saclay)
The point of studying these asteroids is that we have these little specks of dust that were formed and have recorded what happened 4.5 billion years ago. We're playing detective, and we're using our understanding of these little specks of dust to try and go back to the moment of our solar system's formation.
Zahia Djouadi
The idea is to expand the analysis window and to see if I can "get it to talk" more.
Voiceover
The Japanese Space Agency gave the scientists some thirty grains of black sand measuring between 50 and 100 microns, sealed in sample holders. And it's here, on the SMIS beamline, that these messengers from the far-away asteroid belt are going to give their first bits of information.
(Rosario)
So here we have 6 grains from the asteroid on this specimen holder, and now we are going to measure them with the infrared microscope.
(Stefano)
This is a little one, it must measure 50 microns by 50 microns. The IR measurement is obtained taking into account the entire beam passing through this 100-micron window.
Christophe Sandt, scientist on the SMIS beamline (Synchrotron SOLEIL)
Infrared spectroscopy is absorption spectroscopy, so we are going to look at which wavelengths are absorbed by the sample. And with these absorptions, which give relatively fine peaks, we will be able to say "there are such-and-such chemical bonds in the sample", for example we can see if there are silicon-oxygen bonds in the minerals composing the grain, and maybe carbon-hydrogen bonds in the organic matter in the grain.
Alice Aléon-Toppani
So it's a non-destructive technique, but it characterises both the siliceous matter - which makes up mainly the rocks - and the organic matter. Actually it's quite powerful, as we can observe a bit of both at the same time, which is not the case with all other techniques.
Voiceover
After an overall analysis of the grains they will be carefully removed from their holders for a 3D examination using microtomography, at SOLEIL and at the SPring-8 synchrotron in Japan, and they will then be cut into fines sections in order to push the investigations of the Ryugu asteroid even further. The first results are expected at the end of 2021.
Christophe Sandt
We have a whole catalogue of spectra that we can use to compare and identify what kinds of chemical compounds are present in the grains. And the Holy Grail would be to discover unexpected chemical functions too.
Alice Aléon-Toppani
In any case, we don't have this sample in our collections, so we can expect just about anything.
Zahia Djouadi
You can always count on there being surprises! So we're also expecting surprises...