Last year, in an absolute first, a mysterious cigar-shaped interstellar object, dubbed Oumuamua, passed through our solar system.
Astronomers had since been working on reconstructing the extrasolar intruder’s trajectory through space to work out which solar system it originated from but were unable to come up with anything plausible enough to pursue.
Well, not until an international team of astronomers, led by Coryn Bailer-Jones from the Max Planck Institute for Astronomy in Heidelberg, Germany, were able to identify four dwarf stars, any one of which could likely be the home of the mysterious cigar-shaped object.
What went in favor of the four dwarfs is the fact that they are believed to have come within a couple of light-years of Oumuamua, somewhere between one and seven million years ago.
One of the dwarf stars known as HIP 3757 appears to be somewhat reddish in color, while another is similar to our sun and is referred to as HD 292249; however, not much is known about the other two.
“The one that came closest to ‘Oumuamua, at least about one million years ago, is the reddish dwarf star HIP 3757,” said a statement released by the Max Planck Institute.
“It approached within about 1.96 light-years. Given the uncertainties unaccounted for in this reconstruction, that is close enough for ‘Oumuamua to have originated from its planetary system (if the star has one),” the statement continued.
The statement added: “However, the comparatively large relative speed (around 25 km/s [16 miles/s]) makes it less probable for this to be ‘Oumuamua’s home.”
As for the other named dwarf, the Max Planck statement said: “The next candidate, HD 292249, is similar to our sun, was a little bit less close to the object’s trajectory 3.8 million years ago, but with a smaller relative speed of 10 km/s [6 miles/s].”
About the remaining two stars, the institute said that one of them met Oumuamua 1.1 million years ago, while the other came near it 5.2 million years before that, both at “intermediate speeds and distances.”
“These stars have been previously catalogued by other surveys, but little is known about them,” the statement said.
Bailer-Jones and his team’s findings were based on data collected by the European Space Agency’s Gaia probe, which included a whopping seven million stars, as well as 220,000 stars mentioned in the astronomical literature – it was, what you call, information overkill.
“With the new data from Gaia, we have a far better picture of how far away the stars are and how they are moving, which makes this kind of tracing back much more accurate,”
Alan Jackson, an astronomer at the University of Toronto, Scarborough, told NBC MACH in an email, claims the news agency; Jackson, by the way, was not part of the research team.
It must be said, though, that despite the strong likelihood of one of the four stars being the home of Oumuamua, the possibility of the mysterious interstellar object coming from elsewhere can’t be ruled out just yet.
It all began during a routine search of the skies for near-Earth objects in November 2017, when a team of astronomers at the Pan-STARRS 1 observatory on Haleakalā, Hawaii, spotted a bizarre-looking asteroid passing through our solar system.
Being among the first to spot the freak asteroid, shaped like a giant cigar and believed to have interstellar origins, the astronomers named it Oumuamua, which in Hawaiian means a first messenger from far away.
Rob Weryk, a postdoctoral researcher at the University of Hawaii Institute for Astronomy (IfA), said, “Its motion could not be explained using either a normal solar system asteroid or comet orbit.”
Further inspection of follow-up images from the European Space Agency’s telescope on Tenerife in the Canary Islands, by IfA graduate Marco Micheli, revealed that there was, indeed, something unusual about the object.
Combining the data from both centers made it evident that it was an interstellar intruder – an alien asteroid from beyond our solar system.
“This object came from outside our solar system,” said Weryk.
Davide Farnocchia, a scientist at NASA’s Center for Near-Earth Object Studies (CNEOS) at the agency’s Jet Propulsion Laboratory in Pasadena, California, noted that the orbit of the object was “most extreme,” the likes of which he had never seen before.
“It is going extremely fast and on such a trajectory that we can say with confidence that this object is on its way out of the solar system and not coming back,” he said.
Estimated to be a quarter of a mile long, which is ten times its width, OUMUAMUA is dark reddish in color and elongated in shape, somewhat like a cigar, with no gas or dust surrounding it.
“What we found was a rapidly rotating object, at least the size of a football field, that changed in brightness quite dramatically,” Karen Meech said in a statement. She is the lead study author and leader of the research team at the University of Hawaii’s Institute of Astronomy.
According to NASA, the findings “suggest that ‘Oumuamua is dense, comprised of rock and possibly metals, has no water or ice, and that its surface was reddened due to the effects of irradiation from cosmic rays over hundreds of millions of years.”