The asteroid Oumuamua, whose name means messenger in Hawaiian language, was spotted on October 19, 2017 by the Pan-STARRS1 telescope located in Hawaii. It was the first time that astronomers were able to detect an interstellar object “visiting” our solar system. Hence the enthusiasm of the community of astronomers who was able to establish its distant origin by observing its orbit.
When the cigar-shaped traveler was discovered, the researchers first assumed it was a comet, that is, one of the myriad of frozen objects that release gases as they warm up when approaching the Sun. But Oumuamua did not show any activity similar to that of a comet when it was near our star. It was then quickly reclassified as an asteroid – a way of saying it is a rocky body. If its interstellar nature was quickly admitted, the question of its origin was still in debate. Recently, a new study was able to reveal where exactly the mysterious object came from.
Alan Jackson of the Center for Planetary Science at the University of Toronto, in this forthcoming study in the Royal Astronomical Society’s Monthly Notices, undertook to test the effectiveness of binary star systems in ejecting objects. They also examined the frequency of these star systems composed of two stars that orbit around each other in the Galaxy. The scientist and his colleagues have determined that binary stars can eject as many asteroids as comets in interstellar space unlike the Sun, which propels more comets.
Knowing that these systems are in the majority in the Milky Way, and in other galaxies as well, they consider that Oumuamua is very likely to come from such a system. They also assume that one of the two stars of the binary system must have a high mass and a high temperature, because around this type of star there are more rocky objects. For the the researchers, Oumuamua had to be ejected at the moment when the planets of the system were being formed. It will be difficult, however, to determine the precise origin of this asteroid that has been floating around the galaxy for hundreds of millions of years.
Astronomers estimate that an interstellar asteroid passes through the solar system about once a year, but they are very difficult to track. Umuamua is the first of its kind to be discovered. Around the month of May 2018, Oumuamua will be near Jupiter, it will pass near Saturn in January 2019 and it will continue its route towards the confines of the solar system that it will leave towards the constellation of Pegasus.