New research has now been published by Arizona State University astrophysicists, which has also rejected the alien hypothesis.
Instead, Steven Desch and Alan Jackson of the School of Earth and Space Exploration have proposed Oumuamua is an icy chunk dislodged from a Pluto-like planet from another solar system.
Professor Desch said: “In many ways ‘Oumuamua resembled a comet, but it was peculiar enough in several ways that mystery surrounded its nature, and speculation ran rampant about what it was.”
The astrophysicists presented their findings in two papers published in AGU Journal of Geophysical Research: Planets.
The pair analysed the comet hypothesis by highlighting Oumuamua’s unusual characteristics.
Oumuamua is slower than expected of a comet, indicating it had not been tumbling through interstellar space for more than a billion years.
The researchers also failed to detect any gas signatures coming from the object, which usually comes in the form of a comet’s tail.