In 2008, something special fell out of the skies over Sudan, exploding into particles across the vast expanses of the Nubian Desert.
This painful object from above was named Almahata Sitta: a collection of about 600 meteorite fragments, carefully recovered by researchers, and taking the name – ‘Station Six’ – from a nearby railway station.
What was unique about Almahata Sitta was that it represented something never seen before in astronomy: the first time an asteroid effect was successfully predicted by scientists.
Ever since then, researchers have analyzed the splinters of that asteroid – known as the 2008 TC3 – looking for chemical clues about the origin of the mysterious visitor, far from here.
Now, a new study reveals that fascinating story.
Shard AhS 202. (Muawia Shaddad)
Looking at the splinters can tell us about 2008 TC3, which may tell us where 2008 TC3 itself came from – as a celestial array of nested Matryoshka dolls.
“Our amazing result suggests that there is a large, water-filled parent group,” says first author and planetary geologist Vicky Hamilton of the Southwest Research Institute in Boulder, Colorado.
In the new work, Hamilton and fellow researchers had little to do with work, analyzing only the smallest slides of this amazing space rock.
“We were given a 50-milligram sample of Almahata Sitta for study,” Hamilton explains. “We set up and polished the tiny shard and used an infrared microscope to examine his writing.”
The spectrum study revealed something that the scientists did not intend to find. Inside the shard – a chip called AhS 202 – became a very rare form of hydrated crystals, called an amphibole.
This type of mineral requires long bursts of extreme heat and pressure to form, a type not normally considered feasible in carbonaceous chondrite (CC) meteorites.
Micrograph showing amphibole crystals, in orange. (NASA / USRA / Lunar and Planetary Institute)
The attributes show that 2008 TC3 most likely once belonged to a much larger group – something so large in fact, that it would be almost in the same class as Ceres: the dwarf planet, which represents the most well-known in the Solar System’s main asteroid belt, between the orbits of Mars and Jupiter.
“It is thought that most CC parent groups are less than 100 km in diameter, so they would not be large enough to represent the range of pressure and temperature with the mineral accumulation in AhS 202, “the authors explain in their paper.
“So our explanation is that the original parent group of AhS 202 may have been an unknown object, possibly the size of Ceres (~ 640–1,800 km in diameter under the most likely conditions) . “
While this mysterious giant asteroid is thought to no longer exist, the fact that it once inhabited our Solar System suggests that more of the same could have done the same thing. , even though we found no evidence of these large, water-filled bodies in meteorite fragments recovered prior to 2008 TC3.
In the same way that Ryugu and Bennu asteroids reveal some unusual features in a combination that are different from the most recognizable meteorites, the 2008 TC3 multiplication splinters prove that there is more to space rocks than hypothesized. routine able to fully explain.
“We do not suggest that AhS 202 is a celestial analog for Bennu or Ryugu; instead, AhS 202 is a serendipitous source of information about early Solar System products that are not represented by intact meteorites in the collections. us, “the researchers conclude.
“The difference between its mineralogy and known CC meteorites suggests that unique samples such as AhS 202 (and xenoliths in other, non-CC meteorites) may be crucial links that are needed in our understanding of diversity of parent asteroids. “
The results are reported in Astronomy of nature.