New theory explains Oumuamua formation

Hyperaxion Apr 13, 2020

Oumuamua was the first interstellar object discovered in the Solar System. Scientists still try to explain its peculiar orbit and “cigar” shape.

In 2017, astronomers observed the first interstellar object to pass through the Solar System and named it Oumuamua, a Hawaiian term that means “messenger from afar”. Now, a new study published on Monday (13) on Nature Astronomy promises to shed more light on the origin and composition of the strange object, whose “cigar” shape intrigues scientists.

New theory explains Oumuamua formation
New theory explains Oumuamua formation. (Credit: ESO/NASA).

The analyzes were conducted by researchers from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) and the University of California, United States. They used computer simulations to deduce how Oumuamua may have formed. According to them, a secondary gravitational force such as tidal disruption was essential for the formation of the object, as it interferes with the movement of objects in space.

Experts used computer simulations to understand what happens to various objects with orbits close to the stars. For example, if an asteroid passes 60 million kilometers from its parent star, it will be stretched and then shattered by strong tidal disruption, creating a large number of elongated fragments (such as Oumuamua) – some of which would be ejected into the interstellar space.

Illustration shows the tidal disruption process that can give rise to objects similar to Oumuamua.
Illustration shows the tidal disruption process that can give rise to objects similar to Oumuamua. (Credit: NAOC / Y. Zhang).

If the object from which Oumuamua was formed was a comet, what happened was more or less the same thing. Strong gravitational tides shattered the comet and much of the ice on its surface evaporated, leaving a small amount of water and carbon dioxide below the object’s rocky crust.

If that is the case, scientists believe that the residual ice may have served as fuel for the object. Each water deposit may have served as an energy source, and its variable rate of evaporation has driven Oumuamua into such a peculiar orbit.

An object similar to Oumuamua produced by a simulation of the tidal disruption scenario.
An object similar to Oumuamua produced by a simulation of the tidal disruption scenario. (Credit: ESO / M. Kornmesser).

This “tidal fragmentation scenario not only provides a way to form one single ‘Oumuamua but also accounts for the vast population of asteroid-like interstellar objects,” said Yun Zhang, the research leader, in a statement.

The expert also believes that the discovery supports the theory that several other peculiar objects like Oumuamua are out there – and studying them is essential if we are to understand more about other planetary systems. “This is a very new field. These interstellar objects could provide critical clues about how planetary systems form and evolve,” explained Zhang.

Related topics:

Oumuamua

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