Interstellar ‘Oumuamua could have ejected from a binary star system

Researchers believe that the cigar shaped other worldly asteroid that was spotted in 2017 could have been a member of a binary star system.

Named 'Oumuamua, the rocky interstellar asteroid has been intriguing ever since it was spotted on 19 October 2017 and primarily because it is being considered to be the first ever physical detection of a physical object from outside our Solar System.

The new study published in the journal Monthly Notices of the Royal Astronomical Society tries to look at the system from which the rocky interstellar asteroid may have been ejected. Scientists behind the study have been testing how efficient binary star systems are at ejecting objects. They also looked at how common these star systems are in the Galaxy.

This led them to determine that rocky objects like 'Oumuamua are far more likely to come from binary than single star systems. They were also able to determine that rocky objects are ejected from binary systems in comparable numbers to icy objects.

After having determined that a binary system could have been the original home of the asteroid, they also concluded that it probably came from a system with a relatively hot, high mass star since such a system would have a greater number of rocky objects closer in.

The team suggest that the asteroid was very likely to have been ejected from its binary system sometime during the formation of planets.

'Oumuamua has a radius of 200 metres and is currently travelling at a blistering speed of 30 kilometres per second, at its closest it was about 33,000,000 km from Earth.

When it was first discovered researchers initially assumed the object was a comet, one of countless icy objects that release gas when they warm up on approaching the Sun. But it didn't show any comet-like activity as it neared the Sun, and was quickly reclassified as an asteroid, meaning it was rocky.

Researchers were also fairly sure it was from outside our Solar System, based on its trajectory and speed. An eccentricity of 1.2 - which classifies its path as an open-ended hyperbolic orbit - and such a high speed meant it was not bound by the gravity of the Sun.

Major questions about 'Oumuamua remain. For planetary scientists like Jackson, being able to observe objects like these may yield important clues about how planet formation works in other star systems.