‘Exiled’ Ancient Asteroid Spotted In The Kuiper Belt Reveals Our Solar System’s ‘Troubled Youth’

This relic of the primordial solar system is the first carbon-rich asteroid ever detected so far out from the Sun.

Artist’s rendition of the exiled asteroid 2004 EW95.
M. Kornmesser / ESO

This relic of the primordial solar system is the first carbon-rich asteroid ever detected so far out from the Sun.

Astronomers have long theorized that during the early chaotic days of our solar system the newly formed planets kicked out small rocky bodies from the inner regions of the system towards the outer reaches of the Kuiper Belt.

By their estimations, this icy region that lies beyond Neptune should be populated with a small number of carbon-rich asteroids (C-type or carbonaceous asteroids), ejected by the young gas giants and flung billions of miles from where they originated.

So far, researchers have had to rely solely on theoretical models of the early solar system in order to understand its “tempestuous” beginnings, notes the European Southern Observatory (ESO). But a newly discovered relic of those primordial times finally confirms their speculations, bearing testimony to “our solar system’s troubled youth,” shows an ESO news release.

Using the observatory’s Very Large Telescope in Chile, a team of astronomers spotted an ancient asteroid in the Kuiper Belt that shouldn’t have been there.

The space rock, dubbed 2004 EW95, was signaled as an “anomalous” Kuiper Belt Object by its unusual reflectance spectrum, or the pattern of light that it reflects.

“The reflectance spectrum of 2004 EW95 was clearly distinct from the other observed outer solar system objects,” said team leader Tom Seccull, from the Queen’s University Belfast in the U.K.

“It looked enough of a weirdo for us to take a closer look,” he explained.

With the help of the VLT’s X-Shooter and FORS2 instruments, Seccull’s team managed to measure the composition of the 300-kilometer-wide (or 186-mile-wide) asteroid and uncovered that 2004 EW95 is carbon-rich.

This makes it the first carbonaceous asteroid to ever be detected so far out from the sun.

The astronomers suspect that 2004 EW95 was formed in the asteroid belt between Mars and Jupiter and that it got hurled all the way out to the cold reaches of the Kuiper Belt during an early planetary shuffle.

Their theory is based on the ferric oxides and phyllosilicates uncovered by the VLT in the asteroid’s reflectance spectrum. These materials had never been identified in a Kuiper Belt Object before and indicate that 2004 EW95 originated in the inner solar system and was exiled to its present home.

This spectacular discovery is detailed in a paper, published last month in the Astrophysical Journal Letters.

But studying this unique and strange relic of the early solar system proved to be a daunting task. The asteroid is situated very far from Earth, at a staggering distance of four billion kilometers (or about 2.4 billion miles), which makes it difficult to investigate.

Furthermore, 2004 EW95 is not just “very faint” but also constantly moving, notes study co-author Thomas Puzia, from the Pontifical Catholic University of Chile. In addition, the carbon molecules in its composition make it look very dark on the surface.

“It’s like observing a giant mountain of coal against the pitch-black canvas of the night sky,” Puzia pointed out.

Olivier Hainaut, an ESO astronomer who wasn’t involved in the study, chimed in on the team’s discovery.

“While there have been previous reports of other ‘atypical’ Kuiper Belt Object spectra, none were confirmed to this level of quality.”

According to Hainaut, finding a carbonaceous asteroid in the Kuiper Belt confirms the predictions of the theoretical models and shows that astronomers were right about the turbulent early days of the solar system.