A photo illustration shows the first interstellar asteroid: `Oumuamua. This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawai`i. Subsequent observations from ESO's Very Large Telescope in Chile and other observatories around the world show that it was travelling through space for millions of years before its chance encounter with our star system. `Oumuamua seems to be a dark red highly-elongated metallic or rocky object, about 400 metres long, and is unlike anything normally found in the Solar System.
Here is the first observed interstellar object in solar system
01:27 - Source: CNN
CNN  — 

The first observed interstellar object blazed through our solar system more than two years ago.

Astronomers scrambled to observe the object in October 2017 before it disappeared, and their observations caused more questions than answers about the “oddball.”

Now, researchers have used a computer simulation to determine how the object may have formed.

After discovery, the object was dubbed ‘Oumuamua, Hawaiian for “a messenger that reaches out from the distant past.” At first, astronomers expected that it was a comet because it was long believed that the first object spotted in our solar system that originated from outside of it would be one.

That’s because comets can be tossed out of their host systems through gravitational disturbances and they’re also very visible. The second interstellar object discovered in our solar system was an interstellar comet, 2I/Borisov, which was observed in 2019.

But the dry, rocky reddish, elongated cigar-shaped object had no cometary tail, and its tumbling motion couldn’t be explained. And debate has emerged over whether it’s an interstellar asteroid or comet.

And, of course, there was speculation that ‘Oumuamua was a type of alien probe.

So Yun Zhang, postdoctoral researcher at the Université Côte d’Azur and Douglas Lin, professor emeritus in the department of astronomy and astrophysics at the University of California, Santa Cruz, used simulations to show how they believe ‘Oumuamua formed.

The study, published Monday in the journal Nature Astronomy, postulated that ‘Oumuamua was once part of a planetary body in another solar system, ripped apart by its host star before being kicked out into space.

“The discovery of ‘Oumuamua implies that the population of rocky interstellar objects is much larger than we previously thought,” Zhang said. “On average, each planetary system should eject in total about a hundred trillion objects like ‘Oumuamua. We need to construct a very common scenario to produce this kind of object.”

Using simulations, Zhang and Lin modeled what would happen if a smaller planetary body came too close to its host star. They found that if the planet was close enough to the star, within 186,411 miles, it would be ripped into long pieces. Then, they would be shot out into interstellar space.

They also included thermal modeling to determine what would happen to the fragment split off from the planet. Elements like water, would melt on the surface of the object before re-condensing into a strong, stable crust as the object moved further away.

“[This] not only explains ‘Oumuamua’s surface colors and the absence of visible coma [comet tail], but also elucidates the inferred dryness of the interstellar population,” Zhang said.

Astronomers have wondered what is essentially powering the object forward. ‘Oumuamua doesn’t have the tail of a comet, but if condensed water existed on the object, it could be releasing and melting, accelerating the object in a comet-like way. This would explain its odd motions.