Published: Fri, May 11, 2018
Science | By Joan Schultz

Primordial Asteroid Found Roaming Beyond Neptune — Exiled

Primordial Asteroid Found Roaming Beyond Neptune — Exiled

Since objects high in carbon aren't common out in the Kuiper Belt - an icy region past Neptune - verifying their distant existence could further support the current formation theory.

"[These findings] are in agreement with the concept that this item could have formed near Jupiter one of the primordial [carbonaceous] asteroids and has been then emplaced in the Kuiper Belt from the migrating planets", the authors concluded in their newspaper. As they exited their tight orbits and began their outward migrations, their forceful journeys caused small, rocky bodies in the inner solar system to be ejected from their homes, with some making their way all the way out to the Kuiper Belt - an thick and extended ring of comets, asteroids, and other small objects that surrounds the outer solar system.

Why are we telling you all of this?

After painstaking measurements from multiple instruments at ESO's Very Large Telescope (VLT), a small team of astronomers in the United Kingdom were able to measure the composition of the anomalous asteroid, and determined that it is a carbonaceous asteroid.

The answer to the question also goes back to the origins of our solar system. The team of astronomers have some ideas.

Their finding, which was published Wednesday, suggests that 2004 EW95 is the first of a new class of space objects lurking in the outer solar system, in a vast, frigid region known as the Kuiper belt that still contains many mysteries. According to some hypotheses, once the gas giants were formed, the solar system expelled small rocky bodies from within it into remote orbits at great distances from our Sun, particularly towards the Oort cloud and the Kuiper belt. Though observing a dark space rock sitting billions of kilometers away is a scientific challenge in itself, the spectrographs of the telescope helped the team determine the composition of the rock and confirm it's an exiled member of the inner solar system.

"It's like watching a giant mountain of coal against the darkness of the night sky", says Thomas Puzia, co-author of the study and professor at the Pontificia Universidad Católica de Chile.

Astronomers suspect the 300km-long object was formed in the asteroid belt between Mars and Jupiter before being ejected into the outer reaches of the solar system. But although "there have been previous reports of other "atypical" Kuiper Belt Object spectra" - indicating the objects were made of substances not normally found in the region - none were confirmed to the level of quality of 2004 EW95, Olivier Hainaut, an ESO astronomer who was not part of the team, said in the statement.

Dubbed 2004 EW95, the carbon-rich object came to be during the chaotic formation of our stellar neighborhood. "The discovery of a carbonaceous asteroid in the Kuiper Belt is a key verification of one of the fundamental predictions of dynamical models of the early Solar System".

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