An asteroid that was born in the belt between Mars and Jupiter was found floating about in the orbit of Neptune. The asteroid, a 291 km wide space rock called the 2004 EW95 was first spotted because of its composition. It is made of iron, silicon, and carbon, elements that are normally associated with inner Solar System bodies.
EW95 became an object of interest to astronomers after they found that it reflected only a little UV light unlike the other bodies in that region, reports Gizmodo.
Astronomers then used data from the Very Large Telescope, run by the ESA in Chile and found that the rock had a makeup similar to that of other asteroids in the Mars- Jupiter belt.
"It's very carbon-rich," noted Thomas Puzia, astronomy and astrophysics professor at the Pontifical Catholic University of Chile and one of the study's authors. "It's an asteroid that has been very likely flung out from the from the inner solar system, and displaced to the outskirts by interactions with the migrating planets."
There are several theories that attempt to explain how the Solar System was formed and one of them is that planets simply formed themselves based on what materials were available at the time – some 4.5 billion years back.
But why do inner planets look so vastly different from the outer ones? This can be explained through the "Grand Tack" hypothesis. It states that in its initial years, both Jupiter and Saturn should have been a lot closer and then moved a lot further away from the Sun before ending up in their current orbits. This movement and the force of the gravity could have sent a few asteroids hurtling out away from their position, notes the report. The EW95 could be one of those rocks.
Studying these rocks is not easy, say the researchers. "These things are really faint," said Puzia. "You're really pushing the limits of the largest telescopes."
Finding this rock near Neptune could mean that the Grand Tack hypothesis, is in fact more viable now. The idea that Saturn and Jupiter danced around the Solar System, causing a great deal of commotion along the way could be the best explanation so far.
"The next step is to do large surveys and assess the statistical distribution of these objects with this kind of chemistry in the outskirts of the solar system," said Puzia, noting that this observation is only one of its kind and that there needs to be many more made.
The study was first published in The Astrophysical Journal Letters.