A few months ago, astronomers observed the first interstellar visitor of the Solar System, nicknamed 'Oumuamua after the Hawaiian word for scout or messenger from afar. Since then astronomers have been trying to better understand the property of such curious rocky object.
Among these, there’s a new piece of research that suggests that this space rock was likely ejected by a binary system of stars. As reported in the Monthly Notices of the Royal Astronomical Society, it is the nature of the object that sparked the curiosity of the team. 'Oumuamua is rocky, rather than icy like a comet, suggesting that it formed near the center of its star system.
The team calculated which was the most likely scenario for such an object to have been ejected, and since binary systems are a lot more efficient at that than single stars systems like our own they figured that was the most likely. The team also worked out that a binary system should be ejecting rocky asteroids and icy comets at roughly the same rate.
"It's really odd that the first object we would see from outside our system would be an asteroid, because a comet would be a lot easier to spot and the Solar System ejects many more comets than asteroids," lead author Dr Alan Jackson, from the University of Toronto Scarborough, said in a statement.
The analysis conducted by the team also allowed them to work out other likely scenarios of how 'Oumuamua was kicked out by its parent stars. They think that it might have happened during the early years of planetary formation, an idea that is already in the wider debate about the object. They also think that its parent stars are likely very hot, high mass stars.
A previous study had suggested that these type of objects could be extremely common in the Milky Way (over 100 trillion trillion interstellar objects) and they could provide us with important clues on how star systems evolve.
“The same way we use comets to better understand planet formation in our own Solar System, maybe this curious object can tell us more about how planets form in other systems.” Dr Jackson suggested.
'Oumuamua is about 200 meters (650 feet) across and it moves on a very eccentric orbit at about 30 kilometers (about 19 miles) per second. That was fast enough to convince astronomers that it was just a passenger and it originated somewhere far away from here.
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