Astronomers unveil secrets of interstellar visitor

Astronomers unveil secrets of interstellar visitor

The first confirmed interstellar object to be spotted in our solar system is well on its way past Earth after its fly-by in October, but that didn't stop scientists from keeping tabs on it and giving it a name.

Meech and an worldwide research team published their findings Monday in the journal Nature with the title "A brief visit from a red and extremely elongated interstellar asteroid".

That ratio is more extreme than that of any asteroid or comet ever observed in our Solar System.

Scientists expect our solar system receives interstellar visitors like this one several times each year, but they are faint and extremely hard to find, which makes Oumuamua all the more special. They had to be speedy, given that the object is now moving 95,000 kilometres per hour and heading away from the sun.

"This unusually large variation in brightness means that the object is highly elongated: about 10 times as long as it is wide, with a complex, convoluted shape".

Its surface has been darkened and reddened by the impact of cosmic rays over millions of years. We also found that it has a dark red colour, similar to objects in the outer Solar System, and confirmed that it is completely inert, without the faintest hint of dust around it.

It's believed the interstellar interloper could be one tenth as wide as it is long.

So what is it? The presence of 'Oumuamua suggests that previous estimates of the density of interstellar objects were pessimistically low.

But the object has another official name: 'Oumuamua.

The object, named 1I/2017 U1 - or "Oumuamua" a Hawaiian word for scout or messenger from the distant past - varies in brightness by a factor of 10.

Our solar system recently had a very odd visitor. Many decades of asteroid and comet characterization have yielded formation models that explain the mass distribution, chemical abundances and planetary configuration of today's Solar System, but until now there has been no way to tell if our Solar System is typical.

Preliminary orbital calculations suggested that the object had come from the approximate direction of the bright star Vega, in the northern constellation of Lyra. But even at 85,700 miles per hour, it took so long to reach our solar system that Vega wasn't in the same position 300,000 years ago. Imminent upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to produce more interstellar objects in the upcoming years.

Ground- and space-based telescopes, like Hubble and Spitzer, are continuing to track "Oumuamua for as long as they can".

It is travelling about 138,000km per hour (38.3km per second) relative to the Sun, and is now about 200 million km from Earth - the distance between Mars and Jupiter.

Having been able to detect and observe 'Oumuamua, astronomers are hopeful they can prepare to observe other such objects in the future.

Led by Dr. Meech, the team included members from the European Southern Observatory, the Osservatorio Astronomico di Roma, the European Space Agency's SSA-NEO Coordination Center, and the Institute for Astronomy at the University of Hawaii in Honolulu. "And we hope to more accurately pin down where it came from and where it is going next on its tour of the galaxy".