Scientists dazzled by solar system's first-known interstellar visitor

Rodiano Bonacci
Novembre 22, 2017

This unusual object was discovered on October 19 by the University of Hawaii's Pan-STARRS1 telescope. It turned out to be a visitor from beyond our solar system, and it's unlike anything astronomers have seen before.

As per the new findings and analyses published in scientific journal Nature, this extraordinary asteroid had been traveling through the Milky Way since hundreds of millions of years before it got a chance to enter our star system.

Now, new data has revealed that the interstellar intruder is a rocky object, shaped like a cigar, and has a reddish hue.

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 thing is an oddball", said Karen Meech of the University of Hawaii's Institute for Astronomy who leads an global team studying this interstellar interloper.

A research has discovered that an interstellar asteroid that was first spotted passing through in mid-October, is a cigar-shaped object which is quite unlike other asteroids seen in our solar system.

Karen Meech of the Institute for Astronomy Hawaii, says, '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.

The most elongated objects seen to date are no more than three times longer than they are wide, the scientists said.

A brief visit from a red and extremely elongated interstellar asteroid | Nature
Scientists dazzled by solar system's first-known interstellar visitor

So what is it? The asteroid, which has been named Oumuamua, is the first object that has been officially confirmed to be from another star. In addition to the technical name, the Pan-STARRS team dubbed it 'Oumuamua (pronounced oh MOO-uh MOO-uh), which is Hawaiian for "a messenger from afar arriving first".

"For decades we've theorized 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 a statement. "This history-making discovery is opening a new window to study formation of solar systems beyond our own".

But where did it come from? No known asteroid or comet from our solar system varies so widely in brightness, with such a large ratio between length and width.

According to the first round of orbital calculations, this object approached from the estimated direction of the bright star Vega, which is located at the Lyra constellation in the northern sky. But even at 85,700 miles per hour, it took so long to reach our solar system that Vega wasn't in the same position 300,000 years ago.

Because of its speed, if this type of interstellar object were to crash into Earth, it would have a much greater impact and create more energy than an object from our solar system.

The project was funded by NASA's Near-Earth Object Observations (NEOO) Program. "This serendipitous discovery is bonus science enabled by NASA's efforts to find, track and characterize near-Earth objects that could potentially pose a threat to our planet", said NASA Planetary Defense Officer Lindley Johnson. "It is 124 million miles from Earth - the distance between Mars and Jupiter - but its trajectory has taken the object past Mars" orbit, and it will pass Jupiter in May, go beyond Saturn's orbit in January 2019 and then leave our solar system, bound for the Pegasus constellation.

"We are continuing to observe this unique object", said Olivier Hainaut, one of the study authors from the European Southern Observatory.

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