on Only a few days, NASA will bounce the probe OSIRIS-REx off the asteroid Bennu. This mission will collect samples from asteroids and send them back to Earth for further study. This is one of the first of its kind.
That return sample will help us understand not only asteroids, but also the early times when the solar system existed. However, this is not OSIRIS-REx’s only mission.
The probe arrived in orbit Bennu in December 2018 and has been using its toolbar to learn as much as possible about asteroids before long-planned meetings ever since.
And boy, yes. Six individual papers have just dropped into the journal. Science and Scientific advancement It details Bennu’s physical characteristics and how it reveals an incredibly complex history.
“The spaceship has been observing asteroids for almost two years.” Astronomer Joshua Emery Professor at Northern Arizona University and a member of the OSIRIS-REx science team. “Bennu turned out to be a fascinating little asteroid and it gave us a lot of surprises.”
Bennu’Pile of rubble‘Asteroids are exactly what you hear. A relatively loose and less dense mass of rock that is thought to have formed when larger objects are broken and at least some of the material reassembled. For Bennu, the shape formed is a coarse diamond, with distinct ridges at the equator.
Now the first detailed 3D digital topographic map of an asteroid, Led by Michael Daly of York University. This shows that the equatorial ridge is not alone. Another much more subtle ridge extends from pole to pole, indicating that the asteroid is made of rubble, but has internal cohesiveness.
In the past few years we have different Strange things happen in Diamond B (Ie, Bennu).
Last year we discovered that Bennu was ejecting material from the surface. Some of them fell back and some seemed to enter a stable orbit. And scientists Evidence of carbonaceous material Sometime in Bennu’s mysterious past, it alluded to the existence of water.
ㅏ New Global Spectrum Survey A study of infrared and near-infrared asteroids led by NASA-Goddard’s Amy Simon confirmed the presence of carbon-containing and organic matter prevalent on the Bennu surface. asteroid. This is consistent with the hypothesis that asteroids and meteorites can carry parts of life to Earth.
Once there was water
However, there is a more detailed story about the asteroid’s carbon content. The results of a close spectrum study Bright veins of carbonated material passing through numerous rocks.
According to a team of scientists led by NASA-Goddard’s Hannah Kaplan, this is consistent with carbonates found in the “aqueous modified carbonaceous chondrite meteorite”, a carbonate formed through interaction with water.
Some of these veins are meters long and several centimeters thick. Researchers say this is evidence that water once flowed freely over rocks. The asteroid-scale hydrothermal system once existed in the parent body and later Bennu was born.
“Bennu’s maternal fluid flow would have occurred over several kilometers over thousands to millions of years.” Researchers wrote in their papers.
The multispectral image of the surface is Bennu has uneven weathering. In an analysis headed by Daniella DellaGiustina of the University of Arizona. By pseudocolorizing the visible light image of the asteroid, the researchers found that some regions were more exposed to weathering phenomena such as cosmic rays and solar winds than others, suggesting a shock event-like process that exposes fresh material at other times. .
The area of the Nightingale crater where the probe will retrieve samples is fresher material. This means a cleaner view of the material from the early solar system that Bennu is thought to have formed.
And there are more. Temperature change study I discovered something interesting about Bennu’s rock, led by Ben Rozitis of Open University. They are divided into two types: stronger and less porous, and weaker and more porous. Stronger rocks are those with carbonate veins, suggesting that when interacting with water, the liquid seeps the material into the hole, which may ultimately result in stronger rocks.
However, weak rocks are also interesting. They heat up and explode, so they will not survive entry into Earth’s atmosphere. That said, it’s likely some kind of space rock that we haven’t had the opportunity to do up-close research before.
Finally, return to the previously mentioned erupted rock. We don’t know exactly how they are being kicked out of the asteroid. However, the way they fly and come back down is a surprisingly useful tool for investigating the interior of an asteroid.
“It was like throwing marbles so that someone could climb onto the asteroid’s surface and track it.” Research Leader Daniel Scheeres Of the University of Colorado Boulder. “Our colleagues were able to infer the gravitational field from the trajectories the particles took.”
When combined with the gravitational field measurements measured by the orbiting OSIRIS-REx, the team was able to compile the internal density profile of the asteroid. Because denser areas create stronger local gravitational fields.
And they found something amazing. They thought the asteroids would have about the same density overall. But on the surface it looks more dense. The least dense areas are the core of the equatorial ridges and asteroids. It looks as if there is a large void inside.
Since the asteroid’s rotation accelerates over time, it has the potential to rotate itself in the end.
But that’s a long way in the future. For now, the asteroid must be happy with the crater probe’s kiss. And these new analyzes provided researchers with a framework to interpret the scrutiny of studies of those samples as they finally make their way to Earth.