Astronomers say they have detected an asteroid beyond the orbit of Pluto that is in the wrong place. But while odd, it could tell us more about our own beginnings.
Called 2004 EW95, the asteroid is unique in that it is rich in carbon – the first such rock found so far from the Sun. It probably formed in the asteroid belt between Mars and Jupiter before being flung out to its current location in the Kuiper Belt.
The asteroid was studied by a team using the Hubble Space Telescope and the Very Large Telescope in Chile They looked at the light reflected by the asteroid to see how it compared to other Kuiper Belt Objects (KBOs). Their findings were published in a study in The Astrophysical Journal Letters.
“The reflectance spectrum of 2004 EW95 was clearly distinct from the other observed outer Solar System objects,” lead author Tom Seccull from Queen’s University Belfast in the UK said in a statement. “It looked enough of a weirdo for us to take a closer look.”
2004 EW95 is thought to be about 300 kilometers (190 miles) across, although it orbits about 4 billion kilometers (2.5 billion miles) from Earth. This made studying it quite difficult, described as observing a giant mountain of coal against a pitch-black sky.
The discovery of this asteroid is important because it gives us a bit more evidence for one of our key theories of how the Solar System formed 4.6 billion years ago. It’s thought that the gas giants plowed through the young system, causing rocky bodies to be flung out to the outer reaches.
Finding a carbon-rich asteroid like this supports this theory, because it is quite different to other KBOs. That it also contains specific oxides of iron and silicates suggests that it originally formed in the inner Solar System before finding a new home in the icy outer reaches.
“While there have been previous reports of other ‘atypical’ Kuiper Belt Object spectra, none were confirmed to this level of quality,” said Olivier Hainaut, an astronomer from the European Southern Observatory (ESO) who was not part of the team, in the statement.
“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.”