A small meteorite could change our understanding of asteroids

Scientists have released an analysis of a meteorite fragment collected after an asteroid in 2008 near a collision with Earth. They show that the parent asteroid was enormous, and the results suggest that special, aqueous type of asteroids may be larger and have different mineral compositions than previously thought.

The results of the study were published this week in the journal Nature Astronomy and look at the chemical composition of a tile of these meteorite fragments.

The story of the fragments begins in October 2008, when scientists became aware of an asteroid on a collision course with Earth. They knew that most of the rock would burn up at the entrance to the earth’s atmosphere, and that the remains, if any, would fall into the blowing sand of the Nubian desert. It provided a unique opportunity for an international research team, among them NASA scientists, to predict the arrival of the rocks and then comb the sand for any surviving fragments.

Although the asteroid was relatively small – only about nine tons – its damage was minimal. less than 8.8 pounds (4 kg) of meteorite was collected from the desert. They were collectively called Almahata Sitta after a nearby train station. It was the first time an asteroid was seen, and then its meteorite remains were collected.

Since the recovery, various pieces from Almahata Sitta have been analyzed, revealing information about the origin and chemical compositions of various parts of the asteroid. The meteorite test team studiedcalled AhS 202 – was so small that you could place 10 copies of it on a nail head, but it came from a giant space rock, a point of origin that precedes the fragment’s joining with Almahata Sitta’s rocky mass. The team used infrared and X-ray light to study the sample. They found that the fragment was a carbonaceous chondrite, a type of meteorite that formed in the early days of the solar system and that may have brought water to Earth, giving rise to … all of this. Carbonaceous chondrites were generally not previously considered to be able to come from parent bodies (asteroids of origin) that were larger than approx. 100 km in diameter.

But the researchers found tremolite in their fragment of bit, a mineral that requires a huge amount of pressure to form. The existence of tremolites in the sample suggests that the diameter of the asteroid of origin is in the range 398 to more than 1,119 miles (640 to more than 1,800 kilometers), to put it in the wheelhouse of Ceres, the largest object –in fact, a dwarf planet—In the asteroid belt.

“This is evidence of a very large parent body that we did not know existed before,” said Vicky Hamilton, a staff scientist at the Southwest Research Institute and lead author of the latest paper, noting this the first known presence of tremolite in a carbonaceous chondrite. “The fact that we have no other evidence for it in our meteorite collections helps to confirm what we already suspect, which is that the meteorites we manage to find on Earth are a biased sample.”

When asteroids throw through space, they have to come in contact with other bodies. These conglomerations of metals and minerals come together and break as their orbit continues. When a meteorite actually exists on Earth, it is an interconnected compendium of stories from space, and the only way to read it is to do a whole lot of analysis.

“You can have one group of scientists looking at one piece of meteorite and another group looking at another piece of the same meteorite, and you will see two different parts of the history of the solar system,” Hamilton said.

This is how Hamilton’s tile could speak to some origins in a massive asteroid, while another piece of Almahata Sitta might suggest that one-time existence of a proto-planet. The electroscopy work that the team recently performed is a kind of reverse engineering to go from what looks like a typical space stone to its specific story, in this case its reference to a massive parent asteroid. It’s like finding a crumb on your kitchen table – it can be anywhere – but looking at it chemically can tell you the temperature and pressure conditions that gave rise to it, and whether the crumb really came from tomorrow’s bowl or last week’s birthday cake. .

Although much rarer than other types of asteroids, new information on carbonaceous chondrites can fall from the sky at any time. It’s just a matter of whether meteorologists are alert – or lucky – enough to spot them.