Something unique fell from the sky of Sudan in 2008, and burst into shrapnel across the vast and arid expanses of the Nubian Desert.
This burst object became known as the Almahata Sitta: a collection of nearly 600 meteorite bits, painstakingly recovered by researchers, and taking its name – “the sixth station” – from a nearby train station.
Since then, the fragments of that asteroid – called 2008 TC3 – have been analyzed by researchers, looking for chemical clues to the origins of this mysterious, distant visitor.
And now, a new study reveals this intriguing hidden story.
“Our surprising results indicate a large body rich in water,” says lead author and planetary geologist Vicky Hamilton of the Southwest Research Institute in Boulder, Colorado.
2008 TC3 animation. (Astronomical Institute of Charles University / CC BY 4.0)
In the new work, Hamilton and his fellow researchers did not have much evidence, as they analyzed the smallest fragments of these wonderful space rocks.
“A sample of 50 mg from Sitta was assigned to the study,” explains Hamilton.
Spectroscopy revealed something scientists had not expected to find inside the crust – a part called AHS 202 – that was discovered in an extremely rare form of aqueous crystal, known as an amphibole.
This metallic type requires long bouts of intense heat and pressure to form, of a type not usually thought to be possible in the carbon chondrite (CC) meteorites.
The implications of this suggest that 2008 TC3 likely belonged to a much larger object – something so large in fact, that it is actually in the same class of Ceres: the dwarf planet, which is the largest known object in the solar system within the main asteroid belt. Between the orbits of Mars and Jupiter.
In their paper, the authors explain: “Most objects in CC are thought to be less than 100 kilometers in diameter and thus would not be large enough to produce the range of pressure and temperature conditions represented by the aggregation of minerals in AhS 202. As such, our interpretation is that the object is The original for AhS 202 may have been an unknown organism, likely to be the size of Ceres (approximately 640-1800 km in diameter under the most likely conditions).
NASA / USRA / Lunar and Planetary Institute
In the same way that the asteroids Ryugu and Bennu reveal some surprises in formation that differ from most known meteorites, the 2008 TC3 forked fragments prove that there are more space rocks than current hypotheses can fully explain.
The results are reported in Nature Astronomy.