In a new paper submitted to the Astrophysical Journal Letters, researchers at the Harvard Smithsonian Center for Astrophysics suggest the possibility the object is actually a "lightsail of artificial origin".
In a paper to be published November 12 in The Astrophysical Journal Letters, the pair declare that the reddish, elongated, stadium-sized object "may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization", NBC News reported.
However, its flattened, elongated shape, combined with the way it accelerated on its way through the solar system set it apart from conventional asteroids and comets.
At first, astronomers thought the rapidly moving faint light was a regular comet or an asteroid that had originated in our solar system.
Lightsails are a proposed method of spacecraft propulsion which uses radiation pressure exerted from sunlight or large mirrors.
"It is impossible to guess the goal behind Oumuamua without more data", Avi Loeb, chairman of Harvard's astronomy department and a co-author of the paper, told NBC News in an email.
If Oumuamua is a lightsail, he added, one possibility is that it was floating in interstellar space when our solar system ran into it, "like a ship bumping into a buoy on the surface of the ocean", NBC News reported.
Mr Loeb is an adviser to Breakthrough Starshot, an initiative that plans to send a fleet of tiny laser-powered lightsail craft to the nearest star system.
"It's certainly ingenious to show that an object the size of Oumuamua might be sent by aliens to another star system with nothing but a solar sail for power", a senior astronomer at the SETI Institute told NBC.
"Not 'where is the lack of evidence so that I can fit in any hypothesis that I like?"
Mr Bailer-Jones led a group of scientists earlier this year who identified four dwarf stars as likely origin points for Oumuamua.
"Why send a spacecraft which is doing this?" he said.
"News reports that a team of scientists studying the odd, "reddish, stadium-sized" mass that 'tumbled past the sun" in late 2017 say they believe the item could be extraterrestrial in nature, and may not be natural.
'Oumuamua is the first object ever seen in our solar system that is known to have originated elsewhere.
But Loeb called the conjecture "purely scientific and evidence-based", adding, "I follow the maxim of Sherlock Holmes: When you have excluded the impossible, whatever remains, however improbable, must be the truth".