Likely origin found for mysterious visitor from deep space

20 Mar 2018

Illustration of ‘Oumuamua. Image: AuntSpray/Shutterstock

After piquing the interest of an entire astronomical community, we might have an answer to the origin of ‘Oumuamua, an unlikely object in our solar system.

Since the end of last year, astronomers have been left puzzled by the object dubbed ‘Oumuamua – the Hawaiian word for ‘scout’ – as they were unsure of whether it was a comet or asteroid, and where it could have even come from.

Now, however, a team of researchers from the Royal Astronomical Society has published a paper in the journal Monthly Notices of the Royal Astronomical Society revealing that it likely came from a binary star system.

Future Human

Objects such as ‘Oumuamua, the team found, are far more likely to come from binary than single star systems, with the latter often releasing icier objects.

By determining that binary systems are very efficient at ejecting rocky objects – and that a significant number of them exist – the researchers could safely determine that ‘Oumuamua’s origins are from such a system.

An odd discovery

Expanding upon the idea, the team was also able to conclude that the object would have come from a system with a hot, high-mass star because these systems would have one of the highest rocky object densities of any binary star system.

“It’s remarkable that we’ve now seen, for the first time, a physical object from outside our solar system,” said the study’s lead author, Dr Alan Jackson of the Centre for Planetary Sciences at the University of Toronto Scarborough in Canada.

“It’s really odd that the first object we would see … would be an asteroid because a comet would be a lot easier to spot, and the solar system ejects many more comets than asteroids.”

Much clearer picture

Back in February, a team from Queen’s University Belfast helped to piece together the puzzle that was its orbit, the most eccentric ever observed by an object travelling through our solar system.

One possibility that the team proposed was that ‘Oumuamua collided with another asteroid before it was thrown into the direction of our solar system.

The team was also able to find out why the object appeared to be changing colour between measurements.

The answer is that its surface is spotty and when the long asteroid was pointed towards Earth-based telescopes, it was largely red while the rest of the body was grey.

In these first scans, the appearance of red raised the possibility that it contained life in the form of organic, carbon-based molecules.

Colm Gorey was a senior journalist with Silicon Republic