Astronomers expect an interstellar object like 'Oumuamua passes through the inner solar system about once per year, but they are hard to find due to their faintness and quick movement, according to an ESO press release.
The project was funded by NASA's Near-Earth Object Observations (NEOO) Program.
Our current technology has been able to give us some important information about'Oumuamua, but imagine what we'll be able to learn when both the E-ELT and JWST are up and running.'Oumuamua took millions of years to reach us, but with more powerful telescopes, we may be able to see where it came from in interstellar space - and anything else coming our way.
Immediately after its discovery, telescopes around the world, including ESO's Very Large Telescope in Chile and other observatories around the world were called into action to measure the object's orbit, brightness and color.
"This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape", said Karen Meech, who works at the Institute for Astronomy in Hawaii, in a statement. Analysis of its speed and trajectory confirmed that it had come from another star and had likely been adrift in interstellar space for hundreds of millions of years (at least) before encountering our star system.
The observations and analyses were funded in part by NASA and appear in the November 20 issue of the journal Nature.
The asteroid was detected by a telescope in Hawaii.
Unfortunately, the asteroid (named 'Oumuamua), was on its way back to interstellar space when it was spotted, leaving astronomers little time to study it.
None of the known comets or asteroids in our solar system have any resemblance in shape and dimension - puzzling scientists everywhere.
As of Monday, Oumuamua is travelling about 38.3 kilometres per second relative to the Sun, it added.
'Oumuamua made its closest approach to Earth on October 14 - before its discovery - at a distance of about 15 million miles (24 million kilometers), or around 60 times the distance between the Earth and the moon.
Dr Olivier Hainaut, from the ESO in Garching, Germany, said: "We are continuing to observe this unique object, and we hope to more accurately pin down where it came from and where it is going next on its tour of the galaxy".
This week, astromers have been observing this first-ever confirmed interstellar visitor.
But 'Oumuamua's discovery did pose a nomenclature dilemma.
Termed originally as A/2017 UI by the International Astronomical Union, Oumuamua (pronounced Oh-Moo-Ah-Moo-Ah) was spotted on October 19, traveling at an estimated 85,700 miles per hour.
'Oumuamua was seen as a faint point of light moving across the sky.
"For decades we've theorised that such interstellar objects are out there, and now - for the first time - we have direct evidence they exist", said Thomas Zurbuchen, Associate Administrator for NASA's Science Mission Directorate in Washington. Expected to launch in 2019, the JWST will "study every phase in the history of our Universe", including the Big Bang, the creation of our solar system, and its evolution.