Researchers have investigated a mysterious meteorite that exploded over Sudan in 2008. NASA is estimated to have weighed about nine tons and was nearly 4 meters in diameter when it was spotted before impact. After the meteorite entered the atmosphere and hit the planet’s surface, researchers went to the Sudanese desert to retrieve its remains for study. One of those fragments suggests that the meteor likely broke off from a massive asteroid about the size of the dwarf planet Ceres.
Ceres is the largest object in the asteroid belt. The meteorite is known as Almahata Sitta (AhS) and is made from a material known as carbonaceous chondrite. The image above is of a portion of the meteorite in false colors. The space rock’s composition provides researchers with clues as to the parent asteroid that spawned a particular meteor.
The composition of an asteroid can tell scientists how an asteroid was formed. In this study, the team analyzed a 50 milligram AhS sample under a microscope and found that it had a unique mineral composition. Minerals in the asteroid were discovered to have formed at intermediate temperatures and pressures, higher than what you would expect in a typical asteroid, but lower than what you would find in a planet.
One of the minerals was particularly puzzling and is known as amphibole and requires prolonged exposure to water to form. That particular mineral has only been discovered once in another meteorite. The high amphibole content suggests that the fragment researchers are studying broke off from an overhead asteroid that has never deposited meteorites on Earth before.
Many more fragile minerals cannot survive entry into Earth’s atmosphere. Researchers of the study also said they expect the asteroid samples repurchased from Ryugu by JAXA will reveal minerals rarely found in meteorites on Earth.