The interstellar space rock 'Oumuamua has been baffling scientists since the time they spotted it in late 2017, moving swiftly through the Solar System.
Cigar-Shaped Interstellar Asteroid
Among the things that stumped scientists is the asteroid's odd appearance. The space rock looks so different from what they have predicted an interstellar asteroid would look like. 'Oumuamua is long and thin. It is cigar-shaped instead of having the typical lumpy appearance.
Now, findings of a new study shed light on how this mysterious object may have gotten its appearance. In a research published in the journal Monthly News of the Royal Astronomical Society, researchers said that the interstellar rock went through gravitational stretching as it left its star system.
Gravitational Stretching And 'Oumuamua's Shape
Most ejected planetesimals, big objects that wander between star systems, are suspected to come from a system with gas giant planets. 'Oumuamua is an example of a planetesimal and researchers said that it already offers helpful insights in the field of astronomy.
"This object was likely ejected from a distant star system," said study researcher Elisa Quintana, from NASA's Goddard Space Flight Center. "What's interesting is that just this one object flying by so quickly can help us constrain some of our planet formation models."
The intense gravitational pull of gas giant planets can fling objects out of their system and into interstellar space. Using simulations from an earlier study, Quintana and colleagues found that a small percentage of these objects get close to the gas giants as they are ejected.
Researchers said that before it was kicked out of its home, 'Oumuamua possibly had close encounters with local giants and these could be responsible for its current appearance. A close flyby a large Jupiter-like planet with a powerful gravitational tug could stretch a larger planetesimal and tear the object.
The researchers think that the strong gravitational stretching that happened may help explain the cigar-like shape of the 'Oumuamua.
"Using a large suite of simulations of giant planet dynamics including planetesimals, we confirm that 0.1-1 percent of planetesimals pass within the tidal disruption radius of a gas giant on their pathway to ejection. 'Oumuamua may thus represent a surviving fragment of a disrupted planetesimal," the researchers wrote in their study, which was published online on Feb. 26.