An asteroid that had partially disintegrated in the Earth’s atmosphere in 2008, causing the fall of fragments containing diamonds over the country of Sudan, came from an embryo planet that disappeared from our solar system, researchers said Tuesday.
This “protoplanet” that was the size of Mars or Mercury had formed during the first 10 million years of our solar system before being dislocated in collisions with other rocky celestial objects, according to these European researchers.
The asteroid, called 2008 TC3 or Almahata Sitta, was the size of a car. It was spotted by astronomers a few hours before its collision with the Earth in October 2008, which allowed scientists to observe its fall.
Using a powerful electron microscopy technique, scientists studied the composition of diamonds contained in the rock fragments that had dispersed over the Nubian Desert (northern Sudan) after the asteroid explosion.
They concluded that these gems must have formed at high pressures (greater than 20 Gigapascals) requiring the protoplanet to be of size from Mars to Mercury.
Mars (with a radius of 3390 km) and Mercury (radius of 2240 km) are the two smallest planets in our solar system, which formed some 4.6 billion years ago.
These analyzes “provide convincing evidence” that the asteroid comes from a lost planet, which was later destroyed by collisions, says the study published in the journal Nature Communications.
This reinforces the theory that the current planets of the solar system were formed from the remains of dozens of large protoplanets, the researchers add.
The 2008 TC3 asteroid is part of a category of rare rocks called ureilites, which account for less than 1 percent of celestial objects that have fallen on Earth. They are often high in carbon, in the form of graphite and diamond.