Where did the interstellar object 'Oumuamua come from? Its speed could tell us.

[LazyHippo]

An artist's depiction of the interstellar object 'Oumuamua. (Image credit: ESA/Hubble, NASA, ESO, M. Kornmesser)
 

Astronomers will be able to figure out what kind of stars interstellar objects such as 'Oumuamua come from, and therefore something about their compositions, based on their velocity as they enter our solar system, new research suggests.

 

So far, astronomers have discovered only two confirmed interstellar objects (ISOs) in our solar system, 'Oumuamua and 2I/Borisov. They couldn't have been more different from one another: 'Oumuamua lacked any kind of cometary tail, whereas Borisov looked like a typical comet.

 

However, the properties of their home planetary systems are imprinted on both of them, said grad student Matthew Hopkins of the University of Oxford in England, who conducted the new research and presented it at the U.K.'s National Astronomy Meeting in early July.

 

"Because they come from other stars, their properties are going to correlate with those stars," Hopkins told Space.com.

Though we've only spotted two ISOs to date, it's expected that thousands of them are passing through our solar system at any given time, most too far away from us to be detected. However, most or all of those ISOs likely began life as comets around other stars, before an encounter with a Jupiter-sized planet, or perhaps a fly-by star, ejected them into interstellar space.

 

In our solar system, "for every one comet that Jupiter and Neptune pushed into the Oort Cloud, it completely ejected 10, and there are a trillion objects in the Oort Cloud," said Hopkins. Doing the math, it is easy to come to the conclusion that ISOs "are the most numerous objects in the Milky Way galaxy."