Meet Oumuamua: the rogue planet that doesn’t revolve around a star
The interstellar object ‘Oumuamua first caught our attention when it passed through our solar system over two years ago. Was it a comet or an asteroid? Maybe an alien space probe? Guesses kept piling up.
Fast forward to today, and researchers have been able to tap into their technological resources and use a computer simulation to determine how this otherworldly object may have formed.
According to a study published in the journal Nature Astronomy, authors Yun Zhang and Douglas Lin believe the data leads them to the idea that Oumuamua was once part of a planetary body in another solar system – only to be torn apart by its star host before being ejected into interstellar space.
The elongated, cigar-shaped ‘Oumuamua, which means “a messenger from the distant past” in Hawaiian, was first spotted by the Pan-STARRS project at the Haleakalā Observatory in Maui.
Due to its unique shape and ice-free surface, astronomers weren’t sure exactly what they were looking at. Unlike other interstellar visitors, such as Comet Borisov, ‘Oumuamua was rocky and dry, more like an asteroid.
Additionally, ‘Oumuamua showed “non-gravitational acceleration” as it passed through our solar system – a movement that cannot be attributed to tugs by more local and larger objects like Jupiter or our sun.
Next, Zhang, from the Chinese Academy of Sciences National Astronomical Observatories, and Lin, Professor Emeritus of Astronomy and Astrophysics at the University of California, Santa Cruz, considered the possibility that ‘Oumuamua indeed came from’ a system with planets or smaller planetesimals, all orbiting a small, dense star.
Zhang and Lin discovered that if any of these objects approached approximately 220,000 miles from their host star, they would be stretched and torn apart by the star’s immense gravity – an event known as “disturbance.” tides ”. In theory, some of the fragments could be extremely elongated objects like ‘Oumuamua, and they could be ejected into interstellar space.
This “tidal fragmentation scenario not only provides a way to form a single ‘Oumuamua, but also takes into account the vast population of asteroid-like interstellar objects,” lead author Zhang said in a statement.
Moreover, such an event is not uncommon. “On average, each planetary system is expected to eject a total of about 100 trillion objects like ‘Oumuamua,’ Zhang added.
To maintain its odd shape, ‘Oumuamua may have experienced extreme heating during hovers over its native star, and the eventual cooling caused it to develop a hard surface crust.
Ethen Kim Lieser is a technical writer who has held positions at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV.