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Queen's asteroid find sheds light on early days of solar system


Discovery: Dr Wesley Fraser

Discovery: Dr Wesley Fraser

Discovery: Dr Wesley Fraser

A Queen's University astronomer has discovered a fragment from the early days of our solar system - four billion kilometres from Earth.

The first of its kind to be found so far away, 2004 EW95 is a carbon-rich asteroid that currently resides in the Kuiper Belt, a cold region beyond the orbit of Neptune.

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.

While performing routine observations using the Hubble Space Telescope, Queen's astronomer Dr Wesley Fraser noticed something unusual about one of the distant asteroids he was monitoring.

Its "reflectance spectrum" - the pattern of light reflecting from it - marked it out from neighbouring bodies.

"The reflectance spectrum was clearly distinct from the other observed outer solar system objects," said Dr Tom Seccull, a lead author of the study, describing the new asteroid.

"It looked enough of a weirdo for us to take a closer look."

Measurements taken using the European Southern Observatory's (ESO) Very Large Telescope allowed the team to determine it was formed from carbon, suggesting it originated in the inner solar system.

This idea was confirmed by the presence of minerals called ferric oxides and phyllosilicates, which had never been confirmed before in an asteroid from the Kuiper Belt and are another indicator it first emerged closer to the Sun.

These results were published in the journal The Astrophysical Journal Letters.

Despite its distant location, the scientists think understanding more about 2004 EW95 will help them understand the turbulent early days of our solar system.

While it is difficult to determine exactly what went on when the planets as we know them today were forming and taking their current positions, scientists have produced theoretical models to understand this period.

As gas giants such as Jupiter and Saturn formed, they are thought to have migrated through the solar system, causing chaos as they flung small rocky bodies like 2004 EW95 from their places of origin into the solar system's outer regions.

"Given 2004 EW95's present-day abode in the icy outer reaches of the solar system, this implies that it has been flung out into its present orbit by a migratory planet in the early days of the solar system," said Dr Seccull.

Belfast Telegraph