Researchers have observed the first object of its kind - a carbon-rich asteroid in the Kuiper Belt.
Orbiting in the collection of icy rubble beyond Neptune, the asteroid's composition strongly suggests it did not form there.
Instead, the 300km-wide object may have been ejected from an orbit among the giant planets, during the turbulent early history of the Solar System.
The object is so distant, it took scientists several years to analyse, reports BBC.
"When we first actually got the data, we thought we'd got something wrong," Queens University Belfast researcher Tom Seccull told BBC News. "It didn't look like other objects in the Kuiper Belt at all."
Most objects in this region of space have ice-rich surfaces. This asteroid, known as 2004 EW95, is not just carbon-rich but also contains minerals known as phyllosilicates - a family which includes clay and talc.
"The features that we see occur in asteroids that have had their rocks altered by the presence of liquid water," Seccull explains. "Because [2004 EW95] is so far away from the Sun, it's about -235C, so all the water on its surface is going to be frozen."
"This implies it's actually been heated at some point, and could have formed closer to the Sun."
Dr Rhian Jones from Manchester University, who was not involved in the study, noted that this made the findings particularly interesting, "providing the first good evidence for phyllosilicates in a Kuiper Belt object."
"The features that we see occur in asteroids that have had their rocks altered by the presence of liquid water," Seccull explains. "Because [2004 EW95] is so far away from the Sun, it's about -235C, so all the water on its surface is going to be frozen."
"This implies it's actually been heated at some point, and could have formed closer to the Sun."
Dr Rhian Jones from Manchester University, who was not involved in the study, noted that this made the findings particularly interesting, "providing the first good evidence for phyllosilicates in a Kuiper Belt object."
