The study shows that the parent body from which the meteorite came was a planetary embryo of a size between Mercury to Mars.
In 2008, an asteroid measuring 13 feet across penetrated Earth's atmosphere and exploded above Sudan, scattering rocky fragments across the Nubian Desert. Almahata Sitta is the first case in which meteorites have been recovered from a known asteroid that was tracked in space and during its subsequent collision with our planet.
The Almahata Sitta meteorites are extremely interesting, as the specimens exhibit multiple distinct lithologies, ranging from ordinary chondrite to bencubinnite.
There are three formation models for ureilite: shock-driven transformation of carbon to diamond via high-speed impact; chemical vapour deposition inside the solar nebula; and static high-pressure inside a larger body, such as a protoplanet.
The unanswered question, so far, has been the planetary origin of 2008 TC3 ureilites.More news: U.S. v. Microsoft case comes to a quiet end
When researchers at the Swiss Federal Institute of Technology in Lausanne, EPFL, examined several larger diamonds inside the Almahata Sitta meteorites - diamonds with a diameter greater than 100 microns - they identified evidence that the asteroid 2008 TC3 came from a planetary "embryo". Using transmission electron microscopy and electron energy-loss spectroscopy, the team analysed the Almahata Sitta diamonds to see what these mineral inclusions were. These have been known for a long time to exist inside Earth's diamonds, but are now described for the first time in an extraterrestrial body.
The microscopy results showed that these diamonds must have been formed at pressures above 20 gigapascals. Many of these protoworlds collided, their fragments forming new planets and moons.
"Mars-sized bodies were common, and either accreted to form larger planets, or collided with the Sun or were ejected from the solar system".
They concluded the precious stones must have formed at pressures that could only have existed on a long-lost Mars- to Mercury-sized planet.
Sampled from a meteorite that fell to Earth more than a decade ago, this diamond-rich fragment provides compelling evidence of a lost planet that once roamed our solar system, according to a study published Tuesday.