2.02.2024
Meteorites from Asteroid 2024 Bx1, which just hit Earth, may be super-rare space rocks
Meteorite hunters have successfully recovered fragments of an asteroid that impacted Earth over Berlin, Germany, on Sunday (Jan. 21).
A meteorite fragment from asteroid 2024 BX1 (Image credit: courtesy of Peter Jenniskens)
Meteorite hunters have successfully recovered fragments of an asteroid that impacted Earth over Berlin, Germany, on Sunday (Jan. 21) — and the space rocks could be very rare indeed.
The 3.3-foot (1-meter) wide asteroid dubbed 2024 BX1 was spotted by NASA around 90 minutes before it hit Earth's atmosphere. It burned up upon impact, exploding and creating a fireball seen by observers across Europe.
Following the event, on Monday (Jan. 22), intrepid meteorite hunters were out searching for fragments of Asteroid 2024 BX1. One team that hit pay dirt was led by SETI meteor scientist Peter Jenniskens; the crew found the second and third fragments to be uncovered.
"I was incredibly relieved to find these meteorites," Jenniskens told Space.com. "We had walked many tens of kilometers on Monday, Tuesday, Wednesday and Thursday. I was getting a sinking feeling that maybe nothing survived from this — this very aggressive fragmentation."
The meteorites, weighing 5.3 grams and 3.1 grams respectively, were finally discovered by Freie Universitaet students Dominik Dieter and Cara Weihe at around noon local time on Friday (Jan. 26), with the team uncovering yet more samples on Saturday and Sunday.
This isn't Jenniskens' first meteorite hunt.
The SETI scientist had led similar space rock searches for meteorites that came from asteroids detected in space before exploding in Earth's atmosphere. In 2008, for instance, he ran a meteorite-hunting expedition in Sudan as well as 10 years later in Botswana. More recently, Jenniskens found himself in France with a similar goal.
Jenniskens said this particular search, however, was so challenging because whereas meteorites are usually easy to distinguish from more mundane Earth rocks — they tend to possess a dark, smooth look — these fragments strongly resembled terrestrial rocks.
"What we're actually looking for was very different from what most people consider a meteorite," he said. "If you were walking through the fields and saw a rock like this, then you would pass by it."
The official classification of these meteorites hasn't been made yet, but Jenniskens hints that these samples could be something very special. "The next big step in the research is to understand what exactly we're looking at here," Jenniskens said.
"It's very cool."
What sets these meteorites apart?
Denis Vida, a meteor physics postdoctoral researcher at Western University, told Space.com that the parent body of the fragments found by Jenniskens and his team was part of a group of near-Earth asteroids called the "Apollo asteroids."
He added that, thanks to light reflected off its body, Asteroid 2024 BX 1 exhibited an apparent magnitude of 32.8, which makes it one of the faintest asteroids ever discovered. If it had a stony composition, Vida says that the asteroid likely weighed around 2 metric tons.
Some assumptions, such as the size and mass of the asteroid, might be incorrect, however, as the samples recovered appear to be a rare type of space rock, most likely aubrite, according to Vida. He added that this could mean Asteroid 2024 BX 1 was much smaller than estimated, making it one of the smallest asteroids ever discovered.
"Generally speaking, for all types of meteorites, about 10 fireballs drop at least 300 grams of meteorites over an area the size of California, France, or Spain," Vida continued. "Half of them happen during the daytime and go unobserved. The remaining half happens during overcast skies, leaving about two to three that are observable in theory, out of which only a tiny fraction actually get found.
"If meteorites of 2024 BX1 are confirmed to be aubrites, they make up only 1% of all known meteorites, making it very rare indeed."
Vida also explained what else scientists could learn about the now-destroyed Asteroid 2024 BX 1 from these fragments, considering how each meteorite type comes from a specific location in the solar system and has a unique history.
"Currently, there isn't an agreed-upon origin of aubrites, and several candidates have been put forward: The Nysa asteroid family, asteroid 3103 Eger, and even the planet Mercury," Vida said. "With this being a fresh fall, enabling quick lab analysis and such an accurate orbit, I am confident that this rock will get us one step closer to understanding the origin of aubrites and help piece together the story of the formation of the solar system."
Quelle: SC
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Update: 8.02.2024
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Asteroid 2024 BX1 fragments confirmed to be rare meteorites as old as the solar system itself
It's very cool: We have fresh material to look at that may have been the building blocks from which Earth was formed.
A fragment of the Asteroid 2024 BX1 recovered in Germany is a rare class called Aubrite (Image credit: SETI)
Fragments of an asteroid that exploded over Germany on Jan. 21 and were recovered five days later have been confirmed to be a rare space rock type that could help shed light on Earth's origins.
As Space.com initially reported on Feb. 1, scientists suspected that the strange appearance of the meteorite fragments from the parent asteroid 2024 BX1 indicated they were part of a rare group called aubrites. These suspicions have now been confirmed.
SETI Institute meteor astronomer Peter Jenniskens was part of the team that found several of the meteorites. He told Space.com that prior to this, only 11 examples of aubrite meteorite falls had been found on Earth. The incredibly rare samples are from a family believed to represent just 1% of known meteorites.
The aubrite meteorites from 2024 BX1 differ from other meteorites because they have a translucent glass crust rather than a thick crust of black glass, and they have a grey granite appearance. This made them initially difficult to differentiate from standard Earth rocks.
But Jenniskens and collaborators at the Museum für Naturkunde in Berlin performed the first examinations of one of these meteorite pieces with an electron beam microprobe, determining they have the typical mineralogy and chemical composition of aubrite type rocks.
"The interesting thing about this fall is, we have a very nice orbit of it, and so the shape of the orbit itself contains clues as to where the source region for these meteorites was," Jenniskens said. "They likely came from the inner side of the asteroid belt between Mars and Jupiter. That's a place where probably there is a lot of debris, a collision that created a lot of smaller pieces called an asteroid family."
Meteorites that are key to Earth's past and its future
Main belt asteroids like 2024 BX1 were formed at around the same time as the solar system planets, approximately 4.5 billions years ago, from material around the infant sun that was not consumed by the formation of the planets.
That means because they are unaffected by geological processes, they offer scientists a glimpse at the building blocks of the planets, especially the inner solar system rocky worlds Mercury, Venus, Mars, and of course Earth.
Jenniskens added that as aubrites, these meteorites have properties very similar to those of the Earth, such as water ratio and the ratio of other chemicals. This means studying these samples offers the opportunity to investigate the type of material that would have gone into the formation of our planet around 4.5 billion years ago.
"It's very cool. We have fresh material to look at that may have been the building blocks from which Earth was formed. And so that's the appeal of this particular meteorite," Jenniskens added.
Studying the remains of asteroid 2024 BX1 might not just be important in understanding Earth's past but also in safeguarding humanity's future.
Asteroid 2024 BX1 was first spotted by astronomer Krisztián Sárneczky at Konkoly Observatory in Hungary. It was then tracked by NASA's Near-Earth Asteroid Scout and the European Space Agency's Meerkat Asteroid Guard impact hazard assessment systems, both which predicted it would indeed strike Earth.
The tiny asteroid, which was no bigger than 3.3-foot (1-meter) wide and could be one of the smallest space rocks ever detected before it hit Earth, erupted in the atmosphere over Munich, Germany, creating a bright fireball seen across Europe.
This explosion could help scientists better understand asteroid strikes, according to Jenniskens. This is because space rocks that erupt over Earth like this are usually much larger, like the 59-foot-wide (18 meter) Chelyabinsk meteor which exploded over the southern Ural region in Russia on Feb. 15, 2013.
"Here we have a chance to see how a small asteroid behaves when it comes into the Earth's atmosphere," Jenniskens. said. "We can see how it how it fragmented in a very interesting way that deserves a lot more study. That, then may be able to guide forecasts on what altitude a larger object may fragment over Earth."
The SETI scientist adds that this could help us prepare for strikes from smaller asteroids by assisting us to predicted where on Earth their wreckage will fall after they have exploded.
These findings regarding particular aubrite meteorites have now been submitted to the International Nomenclature Commission of the Meteoritical Society on Feb. 2, 2024, for examination and confirmation.
Quelle: SC